Laurent Bougrain

Nanying Liang

Band-specific features improve Finger Flexion Prediction from ECoG

ECoG-based BCIs attract intensive attention recently. ECoG can provide a higher spatial resolution and signal quality compare to EEG recordings. These characteristics make possible to localize the source of neural signals precisely with respect to certain brain activities such that ECoG-based BCIs may realize a complex and apt neuroprosthesis. Signal processing is a very important task in the BCIs research for translating the brain signals into commands for a computer application or a neuroprosthesis. Here, we present a linear regression method based on the amplitude modulation of band-specific ECoG including tap delay for individual finger flexion prediction. We especially study the influence of the frequency band decomposition on the prediction. An efficient feature selection can reduce the number of features by a factor greater than 10 without a strong impact on the prediction. According to the experimental results, the gamma band (60-100Hz) seems the carry more useful information than the others. This method won the BCI competition IV dedicated to this mapping.

I. INTRODUCTION

The goal of brain-computer interface (BCI) research is to reinstall a control and communication capability for those with severe motor disabilities by translating brain signals into commands for a computer application or a neuroprosthesis [START_REF] Wolpaw | Brain-Computer Interfaces for Communication and Control[END_REF].

The neural electrophysiological signals currently being studied in the BCI domain ranges from electroencephalogram (EEG), electrocorticogram (ECoG), to local field potential (LFP) and single unit activity/multiunit activity (SUA/MUA). These different types of brain signals have their own characteristics and there is still controversy on the type of signals which is most suitable for the BCI applications. Nevertheless, considering ECoG whose electrodes are placed over the surface of the cortex, it provides a higher spatial resolution and signal quality than the classical scalp EEG recordings. On the other hand, ECoG is less invasive than those intracortical recordings like LFP, SUA/MUA which by far are only studied in animal experimental BCI systems. By recognizing the merit of ECoG recordings, several groups of BCI researchers have carried out tests on the efficiency of using ECoG as control signals for human BCIs [START_REF] Schalk | Decoding Two-dimensional Movement Trajectories using Electrocorticographic Signals in Humans[END_REF], [START_REF] Sanchez | Extraction and Localization of Mesoscopic Motor Control Signals for Human ECoG Neuroprosthetics[END_REF], [START_REF] Chin | Identification of Arm Movements using Electrocorticograhpic Signals[END_REF], [START_REF] Pistol | Prediction of Arm Movement Trajectories from ECoG-Recordings in Humans[END_REF].

Initially, ECoG electrodes arrays were implanted beneath the dura mater (i.e., under the skull but over the surface of the cortex) for severe epileptic patients in order to identify the sources generating epileptic seizures for presurgical planning. Typically, the diameter of one ECoG electrode is of 4 mm with 1 cm inter-electrode distance. Therefore ECoG can provide a spatial resolution of approximately 1 cm [START_REF] Asano | Origin and Propagation of Epileptic Spasms Delineated on Electrocorticography[END_REF].

Spatial resolution plays an important role in BCI [START_REF] Sanchez | Extraction and Localization of Mesoscopic Motor Control Signals for Human ECoG Neuroprosthetics[END_REF]. The fine spatial resolution of ECoG provides a better opportunity for directly decoding brain activities. Therefore, it is possible to implement direct neural interfaces which are difficult to be accomplished through EEG-based BCIs.

To study the usability of ECoG in BCIs, several research groups had recorded ECoG signals from the participants when they performed certain kind of tasks related to the brain functional areas where the implanted electrode arrays had covered. The tasks include center-out reaching or pointing task [START_REF] Sanchez | Extraction and Localization of Mesoscopic Motor Control Signals for Human ECoG Neuroprosthetics[END_REF], single finger flexion [START_REF] Schalk | Decoding Two-dimensional Movement Trajectories using Electrocorticographic Signals in Humans[END_REF] and cursor trajectory [START_REF] Pistol | Prediction of Arm Movement Trajectories from ECoG-Recordings in Humans[END_REF].

For the application of finger flexion prediction from ECoG, we noticed that a simple linear regression model of amplitude modulation of band-specific ECoG signals was efficient [START_REF] Sanchez | Extraction and Localization of Mesoscopic Motor Control Signals for Human ECoG Neuroprosthetics[END_REF]. In this paper, we made contribution to this method in two ways: first, improve the stability of the model by replacing the inverse operation in the solution of the linear model by pseudo-inverse operation; second, propose to use a stepwise feature selection procedure to select the relevant frequency bands and electrodes. To prove the efficiency of this method, it was applied to the ECoG data set from BCI competition IV, which is dedicated to the task of finger flexion prediction. Results showed that this method achieved the highest value of correlation coefficient between the predicted and true finger flexion recordings.

II. BCI COMPETITION IV -DATA SET 4

The task of the data set 4 in BCI competition IV is to predict the finger flexion from ECoG recordings, which is accessible through [START_REF]BCI Competition IV[END_REF]. Detail description about this data set is found in [START_REF] Miller | Prediction of Finger Flexion: 4th Brain-Computer Interface Data Competition[END_REF], [START_REF] Schalk | Decoding Two-dimensional Movement Trajectories using Electrocorticographic Signals in Humans[END_REF]. Here, we only provide a brief summary. This data set contains three subjects who were epileptic patients under surgical planning by implanting a subdural electrode array to identify the epileptic focus for further surgical removal. They were willing to participate recording experiments: while they performed finger flexion task, the corresponding ECoG and finger flexion time courses were recorded simultaneously. The electrode array was in arrangement of an 8*6 or 8*8 grid (n.b., the exact location of the electrodes was unknown to the competitors because the electrode order had been scrambled in the preparation of this data set).

The subjects were instructed to flex one certain finger by the corresponding word displaying on a screen. The execution of finger movement lasted 2 seconds and it was followed by a 2-second resting period. There were 30 movement stimulus for each finger resulting in 600-second recordings for each subject. The first 400-second recordings were used as training purpose and last 200-second recordings as testing purpose. The subjects were instructed to move one individual finger at a time. Offline analysis of the finger flexion time courses showed that the movements of the last three fingers (i.e., middle, ring and little finger) were correlated in a considerable way.

The ECoG signals were recorded through the generalpurpose BCI system BCI2000 [START_REF] Schalk | BCI2000: A General-purpose Brain-Computer Interface (BCI) System[END_REF], bandpass filtered between 0.15 to 200 Hz and sampled at 1000 Hz. The finger movements were recorded using a dataglove sampled at 25 Hz. Figure 1 provides an example of the visualization of the ECoG signals and the corresponding finger movement time course from subject 1. Due to space limitation, only a subset of ECoG electrodes is displayed. The correlation coefficient between the predicted and true finger flexion time course is used as the evaluation criterion for this data set in the competition.

III. METHODS

A. Pre-processing

Band decomposition: The evidence of sensorimotor ECoG dynamics has been reported in several specific frequency bands including slow potentials, sub-bands (1-60 Hz), gamma band (60-100 Hz), fast gamma band (100-300 Hz) and ensemble depolarization (300-6k Hz) [START_REF] Sanchez | Extraction and Localization of Mesoscopic Motor Control Signals for Human ECoG Neuroprosthetics[END_REF].

Amplitude modulation: Being inspired by the rate coding approach used in spike train decoding, Sanchez proposed a band-specific amplitude modulation (AM) as the descriptor for ECoG signal decoding, which is defined as the sum of the power of the voltage of the band-specific ECoG signals v in a time bin ∆t:

x(t n ) = ∆t t=0 v 2 (t n + t) (1)
where ∆t = t n+1 -t n . We simply let ∆t = 40ms so the resulting band-specific AM features have the same sampling rate (i.e. 25 Hz) as that of the dataglove position measurements. And the band-specific ECoG signals v were generated through equiripple finite impulse response (FIR) filters by setting their band-pass specifications as the frequency band aforementioned: sub-bands (1-60 Hz), gamma band (60-100 Hz) and fast gamma band (100-200 Hz) (n.b., in order to cater the frequency content available in our studied case, the fast gamma band was defined only up to 200 Hz and the ensemble depolarization frequency band was not taken into account). Therefore for each channel, raw ECoG signals were decomposed into three sets of band-specific ECoG signals. Finally, for each set of band-specific ECoG signals, we applied Equation (1) to estimate the band-specific AM features.

Feature selection: Since the ECoG electrode array covered quite a large zone of cortical area, only a subset of electrodes was correlated to the task. On the other hand, we have no a prior information about which frequency band contributed more than the other. Therefore, for each finger and each subject, we use a stepwise feature selection procedure to identify the optimal AM features (i.e., the combinations of channel and frequency band) from the whole set which equals 186, 142 and 192 AM features respectively for subject 1, 2 and 3. The feature selection procedure was based on the method of train and validation (i.e. 3/5 of training dataset are used for training and 2/5 for validation). The stopping criterion is satisfied when the validation correlation coefficient does not increase or when a user predefined maximum number of cycles is reached.

B. Linear Regressor Model

The relationship between the features and the target signals or the interaction between features is not clear for this case. We simply applied a linear model as a decoder for its robustness property. Although, we noticed that other advanced methods have been used for ECoG signals decoding, for example, the Kalman filter [START_REF] Pistol | Prediction of Arm Movement Trajectories from ECoG-Recordings in Humans[END_REF]. This method is not suited for our case because the first method needs a finger model which we do not have. The linear model we used here takes the form as follows:

d(t n ) = W T x(t n ) ( 2
)
where d is the finger position as measured by a dataglove. x(t n ) is the tap-delay AM feature vector x(t n ) = [x(t n )x(t n-1 ) . . . x(t n-k )] T . k is the number of tap-delays and is optimized with the value of 25 for our case. The coefficients W of the model are trained with the Wiener solution:

W = E( x T x) -1 E( x T d) (3)
where E is the expected mean. In order to improve the stability for estimating the coefficients of the Wiener model, we replace the inverse operation in Equation ( 3) by the pseudoinverse.

IV. RESULTS

First, we present the feature selection results. For the feature selection procedure as described in section III-A, we stop the stepwise selection when the maximum number of cycles is equal to 10 or when the correlation coefficient for the validation set does not increase (as the criteria used to justify the similarity between the predicted and true finger flexion in this competition is correlation coefficient). Figure 2 gives an example on the evolution of the feature selection procedure for the index finger of subject 1. The Yaxis indicates the correlation coefficients of training, validation and test set respectively, which are plotted as a function of the number of selected features. We found that there is no evident increment with testing correlation coefficient for more than 4 features from this plot. Figure 3 gives another point of view on the evolution of the feature selection procedure for the same subject and finger. This figure emphasizes the prediction power of each selected feature. Actually, we found that the last 3 features have timid contribution to the task of finger flexion prediction.

Figure 4 shows that the gamma band (60-100Hz) is the most selected band for the 10 best features (1-60Hz: 27%, 60-100Hz: 44% and 100-200Hz: 29%). This is valid independently to the subject and the rank.

Next, we summarize the prediction performance of this method using the testing dataset in terms of correlation coefficient between the predicted and true finger movement in Table I 1 . In order to highlight the effect of frequency- 1 The last element in the table I indicates the correlation coefficient value averaged over all fingers and subjects for the method based on band-specific ECoG, which is slightly different from the result of value 0.46 announced in the competition [START_REF]BCI Competition IV -data set 4 result[END_REF] because finger ring was removed from the evaluation in the competition due to the finger movements of finger ring, by off-line inspection, were quite correlated with those of finger middle and finger little. From Table I, we observed that the method based on bandspecific AM features obtained better performance than the method using raw ECoG signals. It justifies that the decoding power of brain signals lies in certain frequency band and other frequency bands are more likely as background noise. We also provided an example for the predicted finger movement for subject 3 using the method based on bandspecific ECoG AM features in Figure 5. For comparison, the corresponding true finger movement time course is plotted in the same figure.

V. CONCLUSION AND FURTHER WORK

This article proposed a linear decoding scheme based on band-specific amplitude modulation for predicting finger flexion from ECoG signals. The high correlation between the predicted and true finger flexion shows that ECoG-based BCIs is promising for implementing a practical and apt neuroprosthesis. In particular, we can infer from the experimental results that the sensitivity profile of ECoG signals is band-specific. While it is not clear if the frequency parcellation scheme used here is optimal or if it is depended on task and subject.

We also noticed that the method failed in predicting in some cases, especially for the middle finger of subject 1. It is partly due to the considerable correlation between middle, ring and little finger. On the other hand, it is possibly due to the method does not take into account the interaction between the features. We tried to introduce some user-defined interaction terms into the linear regression model. It may improve the decoding accuracy using less number of regressors. Thus, non-parameter models incorporating the interaction terms into the decoding model, for example, using multivariate adaptive regression splines (MARS) [START_REF] Friedman | Multivariate Adaptive Regression Splines[END_REF] will be investigated in the future.

In the stepwise feature selection procedure, we found that some features which did not contribute too much to the prediction of finger flexion alone but ranked high in the sequence of the feature selection procedure. This inspires us to consider the correlation between band-specific ECoG signals.

It is suggested that incorporating the feature correlation into feature selection, for example, using correlation feature selection (CFS) method [START_REF] Hall | Correlation-based Feature Selection for Machine Learning[END_REF], may produce an optimal compact feature set.

Fig. 1 .

 1 Fig. 1. Example ECoG signals: the first 60 seconds of the training data set from channel 46 to 50 from subject 1. The last 5 rows show the corresponding finger movement time course.

Fig. 2 .

 2 Fig. 2. Evolution of feature selection procedure for the index finger of subject 1: the correlation coefficients are plotted as a function of the number of selected features. For each step, the three bars from left to right represent training, validation and test set respectively.

( 1 , 3 )Fig. 3 .

 133 Fig. 3. The X-axis shows, from left to right, the features selected in each step. Each feature is indicated by two elements: channel and frequency band (sub-bands is indicated by 1, gamma band by 2, and fast gamma band by 3). The Y-axis indicates the correlation coefficients of training, validation and test set respectively regarding each feature individually.

Fig. 4 .

 4 Fig. 4. The X-axis shows the 10 best features ranking. The Y-axis indicates the occurence of each frequency band over 15 cases (3 subjects x 5 fingers) concerning the selected feature.

Fig. 5 .

 5 Fig. 5. Predicted (solid red) and real (dash blue) finger flexion time course for the first 60 seconds in testing data set from subject 3.

TABLE I THE

 I PREDICTION PERFORMANCE OF THE METHODS IS PROVIDED IN

	TERMS OF CORRELATION COEFFICIENT BETWEEN THE PREDICTED AND
	TRUE FINGER MOVEMENT FOR EACH FINGER AND SUBJECT. THE LAST
	COLUMN REPRESENTS THE RESULTS AVERAGED FOR EACH SUBJECT AND
	EACH METHOD; THE LAST TWO ROWS REPRESENT THE RESULTS
		AVERAGED FOR EACH FINGER AND EACH METHOD.
	Subj.	Method	Thumb Index Middle Ring Little Av.
		Raw ECoG	0.00	0.13	0.01 0.22 0.06 0.08
	1	Band-specific ECoG 0.58	0.71	0.14 0.53 0.29 0.45
		Raw ECoG	0.26	0.28	0.19 0.34 0.15 0.25
	2	Band-specific ECoG 0.51	0.37	0.24 0.47 0.35 0.39
		Raw ECoG	0.40	0.25	0.31 0.29 0.27 0.31
	3	Band-specific ECoG 0.69	0.46	0.58 0.58 0.63 0.59
		Raw ECoG	0.22	0.22	0.17 0.28 0.16 0.21
	Av. Band-specific ECoG 0.59	0.51	0.32 0.53 0.42 0.48


The transliteration of terms used in the text follows that of the Tamil Lexicon, University of Madras. To simplify the reading, the plural endings (kal ou  ńkal    ) have been omitted.

Governmental institutions vs. associations. The multifaceted expression of Siddha medicine in Tamil Nadu Brigitte Sébastia Siddha (citta 1 ) is one of the codified traditional medicines recognized and supported by the Ministry of the Heath and Family Welfare. It shares the main concepts of ayurveda (āyurveda) but while the texts of ayurveda are written in Sanskrit and this medicine is widespread throughout all India, the textual corpus of siddha is in Tamil language and this medicine is practised in Tamil Nadu, and in some Asiatic and Arabic countries which accommodate a large Tamil community. Siddha is taught in government or private colleges mostly located in Tamil Nadu, and in traditional ways: by hereditary transmission within the family from parents to children (paramparai) or from a master to a disciple (kurukulam). The siddha doctors trained in college tend to practise in towns, like the biomedical ones, while the traditional practitioners are more present in the rural areas where they take care of the population which has not always access to biomedicine. The widespread attitude of traditional practitioners is to maintain secrecy, but some among them have created associations which play a dynamic role for publicising and improving their medicine.

To comprehend the role of associations of traditional practitioners in the promotion of siddha, it is necessary to investigate why and how the governments which carried on since the colonial period have institutionalised this medicine. Two paradigms allow exploring this topic: the creation of siddha courses inside the colleges and the policy of registration of traditional practitioners. The institutionalisation of siddha courses in specialized colleges is quite recent -since 1964-due to the fact that this medicine, in the first schools of Indian medicine, was regarded as similar to ayurveda. Its assimilation with ayurveda, which limited the interest of siddha practitioners to integrate these schools, has resulted by a practice of siddha which is much more in the hands of traditional practitioners than in those of doctors trained in colleges 2 . The situation of the traditional practitioners however is not comfortable due the policy of the registration conducted by the British and Indian governments. It has encouraged the creation of associations of siddha practitioners which oppose a resistance against rules or projects that do not promote siddha or its practitioners. Acting as institutions, these associations play an important role in the development and the promotion of the traditional medicines; their activities complement the work made by governmental institutions, or even, they compensate for their limitations and failures.

Institutionalisation of siddha in Indian medical colleges

The British establishment in India, especially from the second part of 19 th century, was recalcitrant to traditional Indian medicines. For example, the Native Medical Institution created in Calcutta, in 1822, was closed after thirteen years, and then the western medicine became the sole medicine sponsored of the state. The abolishment of this institution was the culmination of the demands of utilitarians and Anglicists to support only western medicine taught in English [START_REF] Arnold | Colonizing the Body. State Medicine and Epidemic Disease in Nineteenth-Century India[END_REF], Bose 2006[START_REF] Brass | The politics of Ayurvedic Education : A case Study of Revivalism and Modernization in India[END_REF][START_REF] Harrison | Medicine and Orientalism: Perspectives on Europe's Encounter with Indian Medical Systems[END_REF]. They considered that the learning conjointly of Indian medicine and western medicine was inadequate due to the incompatibility of their concepts and the 'non-scientific' content of Indian medicine. In fact, the integration of western medicinal courses into Indian medicinal syllabi was a policy implemented since the re-establishment of Indian medical colleges in 1924. This subject, which is still topical, has always been at the heart of debates, either denounced by the practitioners of Indian medicine, or demanded by students who require the same recognition for their medical training as do students of western medicine.

The British rulers in India, however, were unable to develop western medicine in a proper and sufficient way because of the shortage of financial resources and manpower 3 and they were compelled to accept the reintroduction of Indian medicine. On the one hand, their medicine encountered very little interest from Indian population which preferred traditional medicines for the low cost of its drugs, availability of practitioners in rural areas [START_REF] Panikkar | A study of the revitalization movement in Keralam[END_REF], and shared cultural idioms with them. On the second hand, they faced the pressure of Indian medical practitioners and of popular press supported by the leaders of the Independence Movement to get schools of indigenous medicine. Therefore, in order to reintroduce Indian medicine, they created several committees for examining the establishment of a school of Indian medicine and defining the curriculum and textbooks.

In 1918, the British government appointed Dr Rao Sahib M.C. Koman to investigate the different indigenous systems of medicine used in the Madras Presidency, and especially, to determine whether Indian medicines were scientific and effective. As his conclusions did not favour these medicines, the Vaidya Mandal and the Madras Ayurveda Sabha strongly reacted against the British [START_REF] Hausman | Siddhars, Alchemy and the Abyss of Tradition: 'Traditional' Tamil Medical Knowledge in 'Modern' Practice[END_REF]. Muhammad Usman Sahib Bahadur was thus appointed on the 17 th October 1921 to form a committee to explore "the question of recognition and encouragement of the indigenous systems of medicine used in this Presidency (i.e., Madras)" 4 . As a result of the government's enquiry which was: "to afford the exponents of the Ayurvedic and Unani 5 systems an opportunity to state their case fully in writing for scientific criticism, and to justify State-encouragement of these systems" 6 , a full investigation was launched. On the 17th February 1923, Usman presented the report of the Committee on the Indigenous Systems of Medicine to the Government of Madras. In this report, G. Srinivasamurti, Secretary of the Usman committee, recommended the creation of a school of 3 According to V.R. Muraleedharan (1992: PE-27), for 1920s, "there was one medical institution for about every 250 square miles of area, each serving about 77000 people in the presidency." The Usman report points out that there were no more than 3000 medical practitioners who practised the 'European' system of medicine in the Madras Presidency while 21000 practised one of three systems of medicine; see The Report of the Committee on the Indigenous Systems of Medicine, Madras, 1923; the article by K.N. [START_REF] Panikkar | A study of the revitalization movement in Keralam[END_REF] which mentions some statistics of this report.

4

The Report of the Committee on the Indigenous Systems of Medicine, Madras, 1923: 1. 5 Greco-Arab medicine practised by Muslim communities. Indian Systems of Medicine (ISM) in Madras, independent of western medicine, and devoted to the three indigenous Indian medicines, ayurveda, unani (yunāni) and siddha. He considered that the teaching of the three Indian medicines in the same place would be beneficial due to their common features. Although Madras is located in the Tamil area of this Presidency, i.e. where siddha practice is popular, the references to this medicine are very rare in his report which largely mentions ayurveda, and less so, unani. The reason is clearly explained by Srinivasamurthy who wrote: "it is well-known that the Siddha and the Ayurveda have very many things in common including the Tridhatu physiology and the Tridosha Pathology." 7 The preference for ayurveda, on the pretext that siddha was similar, had the advantage of circumventing the absence of textbooks on siddha and teachers available for the students. In contrast, due to the fact that there were private ayurvedic colleges, textbooks on ayurveda were already published in Sanskrit, English and vernacular languages 8 , and teachers could be recruited from graduates of these institutions.

On the recommendations of the report of the Usman committee, a school of Indian Medicine, founded on the 3 rd November 1924 at Madras, was opened the 6 th January 1925 under the temporary responsibility of Srivanasamurthy. Four-year courses were instituted in three sections: ayurveda, unani and siddha. This was a significant change in the policy of Indian medicine, but in favour of ayurveda, and to a lesser extent, of unani. The place credited to siddha remained small, and that, in spite of the opinion of some scholars such as Pandit C.T. Arumugan Pillai Avargal, who stressed the originality of this medicine, notably, its extent use of metals and minerals in its pharmacopoeia 9 . Predominantly in ayurveda, the syllabus of the fourth year included some anatomy and physiology courses, in accordance with the Usman's report:

In the best interests of sciences as well as of suffering humanity, it is highly desirable that the followers of Indian Medicine should study the scientific methods of the West and adopt into their system whatever is useful in Western Medicine and vice-versa (…). We recommended the establishment in Madras of a Central College of Indian Medicine and an associated hospital. The cost of this institution is to be wholly met from State funds, and the resources as regards laboratories, dissection halls, clinical teaching, etc., of existing institutions are to be made available, as far as possible, for the purposes of the new College of Indian Medicine."10 A hospital was attached to the school in 1926, which later shifted to a bigger building rented for the purpose at 'Hyde Park', Kilpauk. Those who had completed the four-year 7 Ibid. 1923: 1. The domination of ayurveda in the field of Indian medicines is also obvious in the Memorandum on the improvement of Indigenous system of medicine by the president of The Madras Provincial LIM Association. The term 'siddha' is totally absent while 'ayurveda' occurs twelve times. (Report of the Committee on Indigenous systems of Medicine, 1948: 479-484). The Memorandum is clear about the concern of LIM focussing exclusively on ayurveda; that can be explained by the presence and influence of Telugu people in the Madras Presidency. This difference is illustrated in the appendix IX of The Report of the Committee on the Indigenous Systems of Medicine which draws up the list of printed texts and manuscripts on ayurveda, siddha and unani. The list A devoted to ayurvedic texts is made up of books used as textbooks and manuscripts, while the list B devoted to siddha texts comprises only manuscripts (1923: 135 and sq.). 9 Both ayurveda and siddha use metals and minerals, but these components are more important in siddha formulae. The treatment of metals in siddha and ayurveda should merit to be compared with that in medicines, such as Arabic, Tibetan or Chinese and western medieval alchemy in order to comprehend how ayurveda and siddha developed.

courses successfully were called Licentiates of Indian Medicine (LIM). However, the LIM remained unregistered until 1933, when a specific register was created for them. These courses were extended in 1930 by an additional year made up of many western medicine courses such as bacteriology, surgery, medical jurisprudence and history of medicine [START_REF] Muraleedharan | Professionalising Medical Practice in Colonial South-India[END_REF].

In 1947, this school was renamed College of Indian Medicine. The question of its affiliation to the University was examined in 1950, but the University authorities were not favorable to award the Bachelor of Indigenous Medicine degree. The government decided thus to create a diploma, specific to this college which was the 'Graduate of College of Indigenous Medicine' (GCIM) degree. In 1955, the college was renamed College of Integrated Medicine, in reference to the synthesis of both Indian and western medicines, and the graduates came under the Integrated Medical Practitioners Act of 1956. Until 1955, the syllabus of courses was made up of 60% of Indian medicine and 40% of Western medicine, but in 1958, the ratio of courses devoted to Indian Medicine felt to 20% 11 , due to the Indian Health Minister who imposed more western medicine subjects. The government of K. Kamaraj (Indian National Congress) took advantage of a student strike which demanded equality of status and salary with their colleagues of western medicine. Then, in 1960, it converted the College of Integrated Medicine into a western medical college known as Kilpauk Medical College which still exists today [START_REF] Brass | The politics of Ayurvedic Education : A case Study of Revivalism and Modernization in India[END_REF]. As the article of Paul R. Brass (ibid: 355) points out, the strikes in the College of Integrated Medicine, Madras, were very widespread. Between 1958 and 1964, "there were at least fifty-five strikes or other demonstrations in the indigenous medical institutions of India". The recurrent demands concerned equalization of salary with that of western medicine, renaming of degree in order to follow the English acronym used in western medical colleges, authorization to be registered as medical practitioners like their colleagues of western medicine, and introduction of western medical subjects in the syllabus.

Institutionalisation of siddha in specific colleges

Few years later, the question of a college of Indigenous Medicine was again reexamined under the pressure of Muttukaruppa Pillai, one of the executive members of the Madurai Siddha Vaittiya Sangham (MSVS), association that will be presented in the second part of the article. The Government of Kamaraj which was not favorable to Indian medicine, finally, accepted that a college of ISM was founded under the control of Madras University, but on condition it was in the South of Tamil Nadu, far from Madras12 . Therefore, under the recommendations of the Mehta's Committee, and with agreement of the University of Madras, a College of siddha, ayurveda and unani was established on November 30, 1964, at Palayamkottai, on the area of a former western medical hospital13 . It could accommodate 30 students in siddha, 20 in ayurveda and 15 in unani who received a B.I.M. degree (Bachelor of 11

The few practitioners who were trained in the college at this period that I have met, present themselves as practitioners both in siddha and in 'allopathy'.

Indian Medicine) after completing five-year courses of which four were devoted to the study of one indigenous medical system and the last one of the three systems. It was only since this time that siddha benefited from a better position in college, and that increased when, in absence of applications for ayurveda and unani, 40 seats were devoted only to siddha. The lecturers of this college were recruited from the graduates of High Proficiency in Indigenous Medicine (HPIM) 14 and of the College of Indigenous Medicine (GCIM), the senior posts were given to the graduates of the College of Integrated Medicine of Madras, the school which was abolished in 1960. The traditional practitioners were not ignored as today, and those with registration (RIMP Registered Indian Medicine Practitioners) were appointed as assistantlecturer. In 1972, post-graduate training and research in general medicine (potu maruttuvam) and in materia medica (kun apāt am) was offered to 10 students in each discipline. Like in western medicine, the diploma was called MD (siddha), Doctor of Medicine (siddha), and obtained after three-year clinical courses and the submission of a thesis.

Once again, the students organized a strike to demand the reintroduction of western medical courses and equalization of their status with that of their colleagues of western medicine. As a result, from the 4th year of courses, they were allowed to study at the Medical College of Tirunelveli, to wear white lab-cloths like those of biomedical students and to use a stethoscope. Lastly, their B.I.M. degree was extended to five and half year in 1977 and was renamed Bachelor of Siddha Medicine and Surgery (BSMS) in the reflection of acronymic degree of the Medical College. This last agreement was obtained after a persistent student lobbying for the creation of jobs in District Hospitals and for improvement of their salary.

This first sidhha college became in 1982 the Government Siddha Medical College, name still used today. It was followed by a second which was opened at Palani in November 1985 for the training of 50 students to BSMS degree. Five years later, this college was relocated into the compound of Arignar Anna hospital, Arumbakkam, Chennai (ayurveda, siddha. Unani hospital), where were added the State office of Council Central Research in Ayurveda and Siddha, the Central Research Institute of Siddha, a large cultivated herbal garden, and the pharmaceutical unit TAMPCOL. Lastly, in 2005, a third college was established on the site of the Sanatorium of Tambaram. It was named the National Institute of Siddha (NIS) also known as Iyothee Dass, a siddha practitioner and a Tamil scholar dalit.

During these three last decades, the strikes organized by siddha students's association have never stopped. In 1991, it was to demand a better stipend, more jobs in Primary Health Centres, updated textbooks, more modern laboratory facilities, and validation of MD (siddha) in cirappu and kul antai maruttuvam, which was not recognized by the Central Council of Indian Medicine, New Delhi. More recently, it was to cancel the project of the creation of an Ayurvedic college at Kottar (The Hindu 13.05.2006; 25.05.2006), to protest against the admission policies of the State Government (The Hindu 05.10.2006), or to question the validity of one-year diploma course in siddha offered by the Tamil University in Thanjavur under distance education mode (The Hindu 01.09.2007). As Brass (1992: 356) has accurately pointed out: "the basic underlying issue for the students is less an ideological confrontation between modernity and tradition than a desire for economic opportunity and improvement in their life aspects." Their demands have indeed two different objectives: either improving the position of siddha which is very disadvantaged in comparison to biomedicine in order to obtain more jobs and best salaries, or getting more western medical knowledge in the view to find jobs in biomedicine. It is necessary to insist that, except for a few (around 5%) belonging 14 HPIM certificates validated the knowledge of one of the three Indigenous medical systems. They have been created in 1929 in Madras Presidency as tests for passed LIM degree (Kandaswamy Pillai 1998: 769).

quite often to siddha families who deliberately have chosen siddha study, the students do not attend these courses as their first choice, but only as their second or third choice, after having failed in the entrance examination to engineering or biomedical colleges. Quite often, after their BSMS degree, they try finding a professional training in a western medical hospital in the expectation to get a job as assistant doctor.

The institutionalisation of ISM reveals controversial attitudes of the British and the Indian governments towards them. Before independence, this approach could be easily understood by the tension between the will of British to impose the supremacy of the 'scientific' knowledge of the west and the ability of the promoters of indigenous medicines to be opposed to Western medicine considered as unsuitable for Indians. After independence, the Indian policy towards indigenous medicines has changed very little compared to that of British [START_REF] Jeffery | Policies towards indigenous healers in independent India[END_REF]. Admittedly, Indian medicine has today a better recognition than in the past, but biomedicine continue dominating the government's choice on spending (90%), and that, in spite of the increasing recourse to the Indian medicines for chronic diseases and their interest regarding low cost and proximity for treating ordinary ailments in rural areas.

The ambiguous policy of registration of practitioners

In his report, Srinivasamurti mentioned the need to register practitioners of indigenous medicine in the means "to discourage the pretentious ignorance and dishonest practice of any particular system whatever it may be." 15 To improve their knowledge, the Government of Madras Presidency, in 1931, created western medical courses that allowed them to be registered as Associate Licentiate in Indian Medicine (ALIM). Nevertheless, all the practitioners of Indian medicine, trained in college as well as by kurukulam and paramparai way, remained unregistered until 1933. In 1918, Krishna Rao Pandulu had attempted to amend the Madras Medical Registration Act of 1914 to extend the registration of practitioners specialized in western medicine to those in Indian medicine, but he met the opposition of the government. Finally, under pressure from practitioners of Indian medicine, the government made provisions to register them by an Executive order G.O. N° 231 P.H. dated February 2, 1933. The Madras Medical Registration Act of 1914 was amended "so as to permit the association of registered Western medical practitioners with institutionally qualified practitioners of Indian medicine" 16 . In fact, graduates in colleges (LIM or ALIM) and nongraduates got registration, but the first under the class A and the second under the class B. This classification, indeed, allowed traditional practitioners to be recognized, but gave a clear preference for training in governmental institutions. It continued being used in spite of repeated demands of associations of traditional practitioners for its abolition this classification, and after independence, the class C was created for nāt t u vaidya/vaittiyar (country practitioners), non-graduate practitioners who were illiterate.

The report of the Committee of Chopra, published at the beginning of independence, presented a few suggestions to regularize the registration 17 . The first suggestion was to establish the Council of Indian Medicine with two sub-sections: one dealing with medical education, inspection and recognition of teaching institutions, and the other with registration 15

The Report of the Committee on the Indigenous Systems of Medicine, 1923: 26. 16 Report of the Committee on Indigenous systems of Medicine, 1948: 128. 17 Ibid 1948: 132-138. The Chopra report justifies the need of registration to protect against quacks, to control the practice, to recognize the good practitioners and to protect them against unfair competition by unqualified persons, and to provide an electorate for the National Medical Board. and discipline. According to the report, the registration must be compulsory in order 'to weed out the quack', and be permitted within a period of two to three years. This suggestion concerned only the practitioners qualified in Indian Medicine from recognized institutions and those who could vouch for ten-year practice in Indian medicine. In 1957, the rules for class B and C practitioners changed and written and oral examinations were instituted to get registration in class B while oral ones for class C. This procedure was followed until 1982.

In 1970, the Central Council of Indian Medicine, Delhi, (CCIM) was constituted. Its first work was to write the Indian Medicine Central Council Act, 1970 (IMCC). Regarding the registration of traditional practitioners, the article 17 (3) of the Act only recognized: a-the practitioners listed on a State Register of Indian medicine who did not possess a recognized medical qualification; b-those who received the privilege to practise any system of medicine conferred by or under any law relating to registration of practitioners of Indian Medicine for the time being in force in any State where they enrolled on a State Register of Indian Medicine; c-those who practised Indian medicine in a State in which, on a commencement of this Act, a State Register of Indian Medicine is not maintained if, on such commencement, they have been practising Indian medicine for not less than five years; d-those who had rights conferred by or under the Indian Medical Council Act, 1956Act, , (102 of 1956) ) on persons possessing any qualifications included in the Schedules to the said Act. Nevertheless, a notification No. V. 26211/4/1976 dated 10.9.76 was added of the IMCC Act of 1970 which put an end to the registration of non-institutional traditional practitioners: i. From the date of the said Notification, namely 1 st October, 1976, the medical qualifications included the second, third or fourth schedule of the Indian Medicine Central Council Act, 1970, are the only recognized medical qualifications through-out the country irrespective of the provisions of the State Acts in this matter. ii. Possession of a recognized medical qualification included in the second, third and fourth schedule of the Indian Medicine Central Council Act, 1970, is a pre-requested and essential condition for enrolment on any State Register of Indian Medicine with effect from 1.10.76.

According to the information collected in the Tamil Nadu Board of Indian Medicine (TNBIM) 18 , the Department of Health and Family Welfare of the Government of Tamil Nadu in G.O. Ms. No 2103 dated 17.11.81, called for applications from all practitioners who had five-year practice before 1.10.71. Nine thousand practitioners sent their application for registration. This proposal, which contravened the notification of the Act, shows that the policy of the government of Tamil Nadu under M.G. Ramachandran (AIADMK 19 ), at the time, was more benevolent towards Indigenous medicine, implicitly, to siddha, than that in Delhi. This benevolence continued under the government of J. Jayalitha (AIADMK) as it launched, in 1993, a campaign for the enlistment 20 of traditional practitioners who had applied in 1982, i.e. when the Central Government called for the end of registration (G.O. Ms No 1172, Health and Family Welfare 2.9.1993). It continued again under M. Karunanidhi (DMK) who established the Tamil Nadu Siddha Medical Council on the 29.9.1997 to develop siddha and to enlist siddha practitioners. However, the CCIM requested the government of Tamil 18 This information is in a 'Brief Note on Enlistment of Indian System of Medicines Practitioners' that the Head of the TNBIM kindly supplied to me.

19

The AIADMK (all India Anna Dravida Munnetra Kazhagam) and the DMK as Dravidian political parties, support much more siddha medicine and Indian medicines, in general, than the Congress.

20

The enlistment was not recognized by the CCIM and thus it did not allow to practise outside Tamil Nadu, to make commercial advertisement, to run a siddha pharmacy or to participate in the elections organized by the CCIM.

Nadu to stop the illegal procedure of enlistment 21 . It is difficult to know how many siddha practitioners have benefited from a certificate of enlistment at this time, and in spite of its legal invalidity, some traditional practitioners who obtained it exhibit it in their office. The question of enlistment is still relevant, and as we will see, it is the main claim of the associations of traditional practitioners of all-Tamil Nadu these last years.

The lack of interest in siddha in the education policy as well as in the registration have incited many children of practitioners to abandon the profession of their forefathers and to take jobs in the Indian administration or, for the richest 22 , to work as biomedical doctor, engineer, teacher etc. Nevertheless, thanks to the revitalization of siddha activated by the Tamil identity awareness, and to the increasing interest in alternative medicine, some of them, after retirement, turn towards the profession of their forefathers 23 . Their knowledge of siddha is variable and widespread ranging from a small competence of those who have practised at part-time or occasionally to a total ignorance. However, they find a means to improve their knowledge through the activities of associations of traditional practitioners which concern the second part of the article.

Activities of associations of practitioners and their role in the promotion of siddha According to the research in Tamil Nadu archives conducted by Gary [START_REF] Hausman | Siddhars, Alchemy and the Abyss of Tradition: 'Traditional' Tamil Medical Knowledge in 'Modern' Practice[END_REF] an association of siddha practitioners existed when Usman was appointed in 1921 to form his committee on indigenous medicine. In order to define detailed proposals for the future School of Indian Medicine of Madras, he pointed out the necessity to work conjointly with an association of practitioners of Indigenous systems formed on the analogy of the British Medical Association. Therefore, the Indian Medical Association chaired by Usman was created from three registered associations of practitioners: Ayurveda Mahamandal, South Indian Vaidya Sangham (siddha) and Eastern Medical Association (unani). Its objectives were to promote the medical and allied sciences, to maintain the honor and interests of the medical profession in general and of the practitioners of Indian Medicine in particular, to maintain adequate standards of professional training and an esprit de corps among members of the association (ibid.: 237 and sq.). To realize them, the association held periodical meetings throughout the country, published a periodical journal, books and leaflets, and tried to form branches all over the country. As we will see, these objectives will be also those of the present associations of practitioners. However, the way to achieve them will differ according to the status of association members, i.e. institutionally or non-institutionally trained practitioners, notably, regarding the place given for learning in associations of traditional practitioners which aims to compensate the institutional education provided by the government.

21

The request for ceasing the enlistment is the object of two letters dated 22.12.1999 (F.No 6-19/98-RQ) and 27.08.2001 (F.No 7-19/2001-RQ) (TNBIM).

22

The economic situation of practitioners is very variable. A few have a large clientele while others receive daily one or two clients. Many have a second source of revenue such as retirement pension, salary, land revenue, rents (shops, houses).

23

It is not rare, when I visit reputed practitioners, to meet some educated retired men not belonging to siddha practitioner families, who are learning siddha. They justify their interest in this medicine by its qualities they deemed as natural, non iatrogenic, effective on chronic diseases, and by their desire to perform 'a service (sēvai) for the nation' by treating patients for free.

The reference to South Indian Vaidya Sangham occurs in the introduction of a conference book dedicated to Muttukkaruppa Pillai 24 . The ancestors of Muttukaruppa Pillai were raja cittavaittiyar and lived at Nattan (Kovilpatti dt) in the palace of a king who depended to the Tirumalainayakkar's kingdom. During the third conference of this association organized in Madurai in 1927, Muttukkaruppa Pillai was encouraged by the founder of the association, S.S. Anandan, to join the Madurai Siddha Vaittiyar Sangham (MSVS) which was created in 1910s and reorganized in 1927 by a group of eminent cittavaittiyar. After having moved to Madurai, he joined this association and became the Executive member in 1932. MSVS was registered in 1941 thanks to the help of A. Vaittiya Natayyar, a friend of Muttukkaruppa Pillai who was advocate, and like him, a freedom fighter, a highly respected figure in India. MSVS is today the oldest and the most affluent association in all Tamil Nadu. It has 4100 members and gathers 58 associations of traditional practitioners (siddha, ayurveda, unani) in all Tamil Nadu which were funded mostly at its one instigation. Apart a few ayurveda and unani practitioners, the members are siddha ones, mostly traditionally trained, with and without registration.

Like the first associations of ayurveda described by Jean M. Langford (2002: 103), the objectives of the MSVS were to oppose a resistance to the lack of patronage of Indian medicine by British. Moreover, the lack of Indian policy for indigenous practitioners reflected along the history of institution of colleges and registration, has forced them to organize themselves into associations. In 1948, Muttukaruppa Pillai launched courses for siddha practitioners and the publication of a journal. According to his son, Rajagopalan, his aim was to enhance the knowledge of traditional practitioners who had more and less a good practice and experience, but often, an insufficient theoretical knowledge, and to sensitize the public to the Indian medicines in the way to counteract western medicine. He established also a manufacture of siddha medicines. That had the advantage, in addition to compensate the lack of availability of drugs on the market, to allow the practitioners to get supplies for their clientele, to begin standardizing medicines and thus to give confidence in siddha products, often denounced for their poor quality and, notably, the misuse of metals. Nevertheless, facing financial difficulties, the association stopped its activities, but the oral and written examinations imposed by the government in 1958 for registration of traditional practitioners in class B and C compelled Muttukaruppa Pillai to revive the association. He founded the certificate of 'Siddha Maruthuva Gurugulam' that was obtained after six-month courses made up of theoretical subjects given by correspondence and a short practical training on preparation of medicines given before the final examination. These courses were instituted to help non-institutionally trained practitioners to pass governmental examinations, but also for those who did not wish to pass examination. They still exist under the supervision of his son, Ragagopalan 25 ; they attract the descendants of hereditary practitioners who want to practise the profession of their ancestors, and persons who choose siddha, either to get prestige and power pertaining to medical professions, or for the valorisation of Tamil identity.

MSVS organizes, every Saturdays, two-hour seminars presided by a traditional practitioner highly involved in the activities of the MSVS. The seminars are attended by 24 All the information on Karuppa Pillai have been collected from his son, Rajagopalan, and from the conference book devoted to Indian Medicines, Madurai, April 17-18, 1971, whose I got a copy from Rajagopalan.

25

Rajagopalan has also inherited from his father the chairmanship of Madurai Siddha Vaittiyar Gurugulam and the co-direction of IMPCOPS, 'the Indian Medical Practitioners's Co-operative Pharmacy & Store Ldt, Chennai. IMPCOPS is a manufacturer of Indian medicines run by a cooperative of practitioners since 1944. The siddha, ayurveda and unani formularies were compiled and published with the help of Srinivasamurthy.

traditional practitioners and by people enrolled in Siddha Maruthuva Gurugulam. Sometimes, a few students from Government siddha colleges are present; they consider these meetings as a means to nourish and complete the knowledge provided by the colleges. The practitioner who chairs the seminars tackles consecutively various subjects such as basic concepts of siddha 26 , description of symptoms of ailments and treatment, formulations and preparation of medicines with a focus on purification of ingredients classified as poisons (metal, mineral and certain plants), notions of anatomy and physiology, and invites his peers to discuss the subjects and to share their experience.

In parallel to these meetings which aim to enhance, and in a certain way, to unify the knowledge of cittavaittiyar, MSVS members are involved in health care service. They organize conferences to inform the public on particular diseases and, above all, they manage free medical care. They propose free medical camps during various festivities in Madurai, notably, in the annual congress AYUSH organized by manufacturers of Indian medicines and attended by governmental and local personalities (State Health minister, director of Central Research Institute of Siddha, MLA, collector). Every Sundays, at headquarters of the association situated in an ancient temple surrounded by a large garden, some cittavaittiyar consult patients against the modest fee of 10 rupees. The medicines are freely provided by the president of the association who runs the manufacture VKS Raja, Tirumangalam, and by some members of the association. These consultations allow the beginner-practitioners who attend Saturday seminars or gurulam courses to learn clinical aspects of siddha from the cittavaittiyar, such as diagnosis, medication, and especially, the reading of pulse which is hardly learnt in the siddha college, in spite of its importance for diagnosis. In fact, the reading of pulse is always practised by students and doctors in siddha college, but the clumsy manner it is done testifies the ignorance of the technique. In fact, they have much more confidence in the stethoscope that symbolizes the medical profession. By comparison, the cittavaittiyar of MSVS strongly put the pulse reading to advantage by justifying that it is fundamental to detect all the diseases and interpret the symptoms. The precision with which they take the pulse, the time and the concentration they attach to the reading, confirm the role they attribute to this diagnostic method.

In the garden of MSVS, Sundays and Thursdays, for rheumatism, dislocations, fractures, and even lumps, people can consult a bonesetter. Under a small shelter, he treats per day around eighty patients by using his own medicine (oil for massage, mineral powder to reduce swelling) and bandages made with pieces of worn clothes hardened by egg whites. In spite of the unhygienic condition of the place and the unaesthetic aspect of the bandages, he receives patients of all socioeconomic profiles who insist on the efficacy and the small cost of his treatment compared with that provided by hospitals. Of course, such reputation is comprehensible if one considers the widespread recourse of fixation surgery, even for common fractures, in private hospitals, which involves long mobilization and high costs.

The activities of MSVS are also proposed by All Travancore Siddha Vaittiya Sangham (ATSVS), but under a different mode due to the fact that this association has created a private college which is recognized by the Government.

ATSVS was created in 1937 at Muncirai, a village which belonged to Neyyatinkara taluk of the ex-South Travancore27 before becoming part of Tamil Nadu. It was founded by 26 This is the humoral theory called tritōs am which is based on the equilibrium of vātam (wind), pittam (fire) and kapam (phlegm); the pañcapūtam, the five bodily constituents and the psychological qualities (kun am). For these concepts: A. Shanmugavelan 1963, P.J. Netiyananda Samikal with the aim to develop siddha. This is clearly expressed in a letter 28 by the Director of Ayurveda, Travancore, dated 8 February 1939, in which he informs the Chief Secretary to Government, Travancore, that the association: "requests the Government for setting apart a sum of not less than Rs 50000 towards the development of the Sidha system of medicine by opening schools, Colleges and Pharmacies and by providing grants to Sidha Vaidhya institutions; for appointing a competent person, well qualified and experienced in the Sidha system for efficient administration and development of the science; and helping the ATSVS by granting a free registry of not less than 100 acres of land for the cultivation of medicinal herbs and plants." As the tone of letter shows, the Director of Ayurveda considers the demands as "too extravagant" and advices the government that, before taking any initiative, the ATSVS "has to establish its claim for it by its service and useful at least to the public in the locality where it proposes to function."

Finally, on the vast land belonging to ATVSV, a small school was established to teach siddha to children capable to read and write, and then, to hereditary and traditional practitioners. After two-year courses, the practitioners got the Certificate of Siddha Practitioner. This certificate was recognized since 1947 by the State of Travancore-Cochin, but the merger of this area with the State of Madras resulted in the lost of this recognition due to the regulations applied by the Tamil Nadu Government. The school became a College managed by Dr Mohanraj who inherited the function from his father, the successor to the founder. After a long battle, Mohanraj got the permission in 2001 from the Department of Health and Family Welfare of Tamil Nadu to accommodated 30 students for BSMS degree, and I have obtained recently the authorization for welcoming 10 students more thanks to the new building erected by the association. Nevertheless, he has not succeeded in opening postgraduate courses which exist only in Governmental colleges. The students benefit from practical training in the hospital established in the property. The hospital receives 100 to 150 outpatients per day and has 10 beds which are quite often unoccupied. The fees of study which cover also the accommodation in hostel are very high in comparison with those of governmental siddha colleges, but the manager justifies them by the fact that the hospital is necessary to the training of students, and thus, the fees must cover the expenditure of freetreatment of patients.

This area belonging to Kanniyakumari district is very famous for siddha which is practised mostly by traditional practitioners. Small villages with three to five cittavaittiyar, quite often of nāt ār caste, are not rare. Therefore, a great attention is paid to the syllabus of this college which completes the curriculum of government siddha colleges with specialties very popular in this area: treatment for snake venom and varma therapy (acupressure on vital points), and subjects fundamental to traditional practitioners: preparation of medicines and pulse reading. The traditional practitioners are critical about the education given in the colleges which neglects the knowledge of cittar29 such as pulse reading, yoga, preparation of medicines. In the government siddha college, kun apāt am (materia medica) is an important specialization, but it tends to focus on pharmacology and pharmacognosy. The students have only one-year training in the preparation of medicines and the purification of metals and minerals, and they do not learn to prepare some complex metallic products such as kat t u. Obviously, given that the most of students will find jobs in governmental institutions and in private clinics where they will use ready-made medications sold by manufacturers, their interest in the preparation remains limited. Let add that the traditional practitioners are also critical about the quality of ready-made drugs because they are produced with electrical machines which, because of their heating effect, reduce the efficacy of the medicines. Concerning toxicology, yoga and varma therapy, these specialties also are inscribed in the syllabus of governmental colleges 30 but they are hardly taught and practised.

ATSVS continue providing certificates to siddha practitioners. They are given after two-year seminars at the rate of two-hour course one Saturday per month. In comparison with the seminars organized by other associations, the courses of ATSVS are well structured and educational: the participants receive a photocopy of formulae which are commented by the president; they are never requested to partake their knowledge or to expose their experiences about treatment, nosography, or medicinal preparations. The formulae presented in seminars are those which are used to prepare medicines inside the hospital and it is expected that they will be used by practitioners who attend the seminars. These recipes come from the ancestors of Mohandaj, some ācān, and manuscripts (ōlaiccuvāt i) belonging to his family and to hereditary practitioners. Concerning the manuscripts, some students and professors are involved in the work of deciphering, interpretation and transcription of their content into usual language. The ōlaiccuvāt i constitute an important part of the knowledge of traditional practitioners, but nowadays, they are scarcely used because rare are the practitioners capable to read and understand them; they prepare medicines from formulas which were rewritten from manuscripts in notebooks by their parents. Therefore, ATSVS plays an incontestable role in the institutionalization siddha by taking great care to give a good schooling to the students in respect of both, the syllabus defined by the government and the traditional practice, and to the traditional practitioners in respect of the tradition, with academic methods.

The education is also the field that Dr Rajendran, the founder of an association newly established, has well developed besides numerous activities aiming to enhance the knowledge of siddha.

Rajendran has a clinic which is situated in a small village near Takkalai (Kaniyakumari Dt.), not far from Muncirai. The clinic has forty in-patient rooms and receives daily more and less one hundred outpatients suffering of arthritis, hemiplegia, diabetes, high pressure, fever, headache, chikungunia etc. Rajendran learned siddha from his father who died when he was 14. Despite his young age, he continued to treat some patients of his father after the school. He studied homeopathy in Nagerkovil, and in Salem where he got his MD degree. In fact, he does not practise homeopathy that he studied in order to get a degree to open a clinic 31 . Much more interested in siddha, he improved his knowledge about formulae, diagnosis, yoga, varmakkalai which comprises varma and cilampam 32 , venom treatment, bone setting, from ācān (master, guru), 47 according to him. 30 Varma begongs to cirappu maruttuvam or special medicines which comprise: tōl nōy (skin disease), kirikai nōy (mental illness), yoga, varma, kayakarpam (rejuvation) while nañcu maruttuvam or toxicology is one of the six specialties proposed at Palayamkottai; the four other are: potu maruttuvam (general medicine), kun apāt am, kul antai maruttuvam (pediatrics); nōy natal (pathology) 31 Entrance in homeopathy colleges requires lower marks and fees than in biomedicine or Indian medicines.

32

Varma and cilampam are associated arts practised mainly by nāt ār community in the South districts of Tamil Nadu. This community, known also as cānār, was traditionally toddy tapers, and to treat injuries due to fall from trees, some families are specialized in bone-setting and in acupressure on

In 2000, Rajendran created the association 'Power Trust India' from which he founded in 2001: a manufacturing unit of siddha medicines under the trademark 'Power lab India'; a herbal store at Takkalai for raw material and medicines; a Kalari association for the development of this martial art also named cilampam; a community college to prepare diploma of female health assistance and of varma and massage science awarded by the department of Community College of Manonmanian Sundaranar University, Tirunelveli; Ambuvanam, an association which consists in two siddha hospitals established in rural areas employing qualified doctors and traditional practitioners along with students and nurses trained in his college; and lastly SAVKIA (Siddha, Ayurvedic, Varma, Kalari International Association), an association made up of traditional practitioners.

He decided to create SAVKIA in order to invite traditional practitioners to reveal their knowledge to others: Some practitioners have some knowledge but they hide it and they don't accept to share it. So, I decided to improve this situation and I seek to encourage the people to bring out from their mind, original formulations and correct formulations and to bring them to the patients in such a way as to be of service to the nation. This explanation results from his experience with traditional practitioners with whom he spent a lot of time and energy before obtaining little information to enhance his knowledge and practice of siddha. Therefore, he organizes a monthly meeting which gathers together students of varma and nursing and traditional practitioners, in which he invites ācān and practitioners to reveal some of their formulae, to explain the meaning of verses of cittar and concepts of siddha, and to talk about their healing experience. The content of meetings is inspired by that of All India Siddha Vaittiyar Sangham of Nagerkovil, established in 1976 on the model of Madurai Siddha vaittiyar Sangham. Nevertheless, the meetings organized by SAVKIA distinguish themselves by the presence of students who have the opportunity to meet traditional practitioners and to benefit from their knowledge and experience.

Rajendran is one of the most innovative, motivated and ambitious siddha practitioners that I have met. The term 'International' added to the name of his association sets the tone of his ambition. His last creation is a monthly journal whose the publication has been possible thanks to his relationship network, and he is expecting to launch a website "to expose the world to siddha". He is well informed about the difficulties in exporting siddha products to western countries due to the regulations about the use of toxic metals and poisonous minerals, and his objectives are based on the selling of siddha medicines as well as on the development of a network of siddha practitioners. On the regional scale, he succeeded in developing varma courses in five governmental and private universities scattered in Tamil Nadu where this therapeutic specialty is hardly known, and he expects to cross the frontiers of Tamil Nadu and of India.

In establishing his community college, Rajendran had two objectives: to train rural youths for medical jobs by mixing western approaches (anatomy and physiology) with traditional knowledge and know-how; to allow those who cannot enter in siddha colleges, notably children of hereditary practitioners, to obtain a diploma recognized by the government for practising varma and thus to work in connection with siddha. The reputation of varma is increasing nowadays, and as I observed several times, siddha doctors begin to employ varma practitioners; some of them were trained by Dr. Rajendran. These varma courses also attract vital points. In the past, some families were rajavaittiyar for Tamil rulers to whom they practised varmakkalai, either to neutralize or to kill their enemies, or to care the varma points injured during the battles. For a parallel with Kerala's practice of marma and kalari payat t u, see P. B. Zarelli (2006).

students of siddha college of Palaiyamkottai who wish to learn this speciality, and also, to enhance their knowledge from the traditional practitioners one.

Associations acting as institutions

Created by traditional practitioners, these three associations have, for the main objective, to get recognition from the government and from the public. If traditional practitioners played an important role in the beginning of the institutionalisation of indigenous medicine, and notably of siddha, by prompting creation of college, by writing text-books, by founding or taking part to foundation of pharmaceutical units such as IMPCOPS, they face today the mockery of the Indian medicine doctors trained in college. These doctors, who do not belong to traditional siddha families, claim to possess a medical knowledge highly superior to that of traditional practitioners due to the fact that they learnt it scientifically, i.e. through western educational methods and medical subjects. They deem that the traditional practitioners are ignorant and incompetent, and partly, responsible of the decreasing interest for traditional medicine, especially, siddha. In fact, these two categories of practitioners are very opposed, by their practice as well as by their interest for promoting siddha. The associations of students are much more committed to defend their interests as future doctors through recurrent claims to increase the number of jobs, salary, and westernisation of their college syllabus, than to develop siddha medicine. It is also the case of associations of siddha doctors trained in colleges which are always ready to take actions against projects that disadvantage siddha practice, as for example, in 2006, the establishment of an ayurvedic college at Kottar (near Nagerkovil) or the creation of ayurvedic rejuvenation centres in Tuticorin district, or to valorise siddha -in competition way with ayurveda-for its large use of herbals, skipping parts on one's revision on metals and minerals which hold a wide place in the material medica 33 .

The traditional practitioners associations are preoccupied by the future of their practice, but their main concerns are much less job and financial opportunities or competition with ayurvedic or unani, than the preservation of medical knowledge and how-know of all traditional systems, and the defence against government rules. They are very aware that their knowledge is endangered by the policy of the government which, on one hand, recognizes only people who are trained in college, and on second hand, is much more interested in developing western medicine because of the financial and political benefits. Political relations, unquestionably, have played a role in the development of the associations, if we consider the ability of MSVS to open a siddha college, to diminish the taxes imposed on practitioners, to get the participation of the officials and politicians to their conferences, that of ATSVS to obtain the government's authorisation to train BSMS students and that of Rajendran to open courses in various Universities. Nevertheless, all their demands are not satisfied, notably, those concerning the registration. Once again, the registration has been in the heart of concerns of all traditional practitioners associations in 2007 when MSVS has 33 This attitude is well expressed by the association of the 'Friends of Siddha Medicine'. Among its activities which claim to defend siddha medicine, it organizes conferences on this medicine. Nevertheless, the term of siddha used in the title of these conferences is inadequate because each of the 50-60 communications presents a particular plant on the point of view of its use, proprieties, active principles or micro structure. Siddha of course uses these plants, but other traditional medicines too, and moreover, it uses in association with many constituents that makes the pharmacodynamy analysis difficult. These communications, in fact, are in coherence with the new objectives of research centres on traditional medicines which are to produce medicaments from one plant or two-three maximum in order to analyse the pharmacodynamy and to optimize their standardisation if the plants used are easily available or cultivated. launched actions to renew the enlistment certificates obtained between 1993 and 1997, and to provide new enlistment for competent practitioners. In September 2007, a large conference titled 'Traditional Scientific Siddha Medical Conference 2007' gathering all the associations of traditional practitioners of Tamil Nadu was organised in Madurai. Its aim was to hand thousands of applications of cittavaittiyar justifying ten-year practice over to the government members and politicians in order to force them to grant registration. Such demand had already been submitted in 2000 to the government of Jayalitha without success [START_REF] Silvarajan | Ceyalar urai: Alaikkirom[END_REF] and the leaders of associations expected that the newly elected government of Karunanidhi would be more benevolent. However, the Health Minister invited to the conference rejected the demand and invited the unregistered practitioners to pass a certificate course prescribed by the Government 34 . This refusal after months of negotiation is not surprising if one considers the strong opposition of the Central government to enlistment and its concern to put an end to the quackery. Avoiding quackery is a reason for which associations of traditional practitioners have developed activities such as schooling, publication of textbooks and journals, manufactures of medicines which, to some extent, participate to the standardization of this medicine, and implicitly, respond to the demand of the World Health Organization and the Indian government. On one hand, they help the hereditary practitioners to enhance and exchange their knowledge and how-know, and on the other hand, they offer to those who are badly trained a means to learn siddha. Nevertheless, as they accept everyone, with and without medical background, they give the opportunity to unskilled people to become siddha practitioners. These people may get the legitimization of their practice by subscribing to correspondence-course such as those of Madurai Siddha Vaittiyar Gurukulam in order to get a diploma. Therefore, though the associations aim to improve the knowledge of practitioners, and also of students trained in colleges, in order to enhance the reputation of their medicine and to standardize its practice, controversially, they favour quackery which, according to many skilled siddha practitioners, would represent 90% of the profession.

By their activities, these associations of traditional practitioners play a role very parallel to that of the government. They institutionalise siddha through educative systems, diplomas, journals and books. Like the government, they organise exhibitions on medical plants, and give free or cheap consultations, actions that they explain as pertaining to the philosophy of the cittar which consider generosity, disinterest and humility as the fundamental qualities of cittavaittiyar. Nevertheless, one should not forget that the president of MSVS is the owner of VKS Raja (siddha pharmaceutical unit), that Rajendra is building an unit to produce siddha medicines and that ATSVS has built new building in order to welcome more students, and thus, the wish to attract clients who ordinary consume western medicines is certainly a reason which justifies charitable acts. Some of these associations are even involved in the preservation of the traditional knowledge through the collection and treatment of ōlaiccuvāt i. This activity is one of the priorities of the Central Research Institute of Siddha, Chennai, which often solicit traditional practitioners to get their manuscripts, but without success. Nowadays, the practitioners refuse to give their ōlaiccuvāt i to them and, if they do not wish to keep them with us, they give them to other traditional practitioners such as Dr Rajendran or Mohanraj who collect them in order to discover new formulas.

Indubitably, because of their parallel activities, the traditional practitioners associations are not to please to the siddha doctors trained in college and working in governmental institutions, and certainly, they contribute to strengthen the lack of communication and disagreement between these two categories of practitioners.

34

The Hindu, September 24, 2007; personal communication with the committee members of MSVS.

6

  Ibid. 1923: 1.

  8

  launched a campaign for the merger of the Tamil speaking regions of Southern Travancore with the neighbouring area of Madras. Under the State Reorganisation Act of 1956, the four southern taluks of Travancore and a part of the Shenkottai taluk were merged with Madras State on November 1, 1956 (Sathianesan 2000). 28 File n°546/42, bundle 207, L.G.B, Revision of syllabus of studies on Ayurveda. Appointment of part-time lecturers at the Ayurveda College for teachers of Anatomy, Physiology, etc., Kerala State Archives, Tiruvananthapuram.

  Thottam 2000, C.S. Uthamaroyan 2005.

 Ibid., 1948: 26; 30.

The fact that this college should be established in the South of the State is a reflection of the reputation of the South districts which persists even today, considered as backward, underdeveloped and traditional.

In fact, Muttukaruppa Pillai had chosen Kuttalam to establish the college. Kuttalam is a small village situated in the foothills of the Western Ghats at about ten kilometers from Tenkasi, renowned for the therapeutic properties of the water at its waterfalls. However, this village having no facilities to welcome the college, Palayamkottai was preferred.

On July 1948, the State of Travancore-Cochin was established, with the Maharajah of Travancore as the Rajapramukh of the new State. In 1954, the Travancore Tamil Nadu Congress

Person who is realized; yogi -18 according to the Tamil tradition-whose certain are considered as the authors of Tamil medical manuscripts.