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VII. Note relative to the Electricity developed by Muscular 

 Contraction. By M. C. Despretz *. 



THE note which I have the honour of communicating, is a 

 simple enumeration of the experiments which I made with 

 the view of reproducing the phaenomena announced by M. 

 Du Bois Reymond of Berlin t. I shall not discuss these phaeno- 

 mena, my only object being to reproduce them. This appears 

 to me the most philosophical manner of proceeding in the ap- 

 preciation of a new fact. We are not sufficiently acquainted 

 with the intimate nature of bodies, of heat, light or electricity, 

 we know too little regarding vital phaenomena, to reject h 

 priori a physico-physiological fact, however singular it may ap- 

 pear at first sight. The wisest and most prudent course is, 

 first to confirm it, and afterwards by a profound analysis of 

 the phaenomenon, to ascertain the various sources of error to 

 which it is exposed. It must not be forgotten that Galvani's 

 researches upon animal electricity have given rise to one of 

 the most important discoveries of modern times. 



I shall not enter further upon the history of the subject, in 

 doing which I should have to quote numerous researches, and 

 particularly those of the illustrious philosopher who made 

 known to the Academy the principal result obtained by M. 

 Reymond, and whose name is connected with so many import- 

 ant researches which have been made since the end of the last 

 century. 



I have not inserted in the Comptes Rendus the results of the 

 experiments which I alluded to at the last meeting of the Aca- 

 demy, because these results did not appear to me sufficiently 

 demonstrative. The only conclusion I should deduce from my 

 first experiments, would be the uncertainty which the inter- 

 vention of the metallic plates in galvanometers appears to me 

 to throw upon the results of many experiments, as I have had 

 the honour of stating to the Academy. 



The galvanometer which I used was made by M. Ruhm- 

 korff, whose skill is well known. The diameter of the wire was 

 Y^^th of a millimetre, and its length 800 metres. The wire 

 made about 1800 convolutions round the frame of the appa- 

 ratus. The delicacy of the instrument is shown by the fol- 

 lowing numbers. 



A copper wire |ths of a millimetre in diameter, when im- 

 mersed to a depth of 2 centimetres, afforded a deflection of 3° 

 in distilled water, 25° in the water of the river Seine, and 68° 

 in a solution of chloride of sodium, containing from four to five 

 per cent, of the salt. ^ 



Plates of gold, the surfaces of which were nearly one square 

 • From the Coviptcs Rendus for May 28, 1849. 

 t Comptes Rendus, May 21; and Phil. Mag. vol. xxxiv. p. 543. 



