100 MEMOIR OF MAGENDIE. 



In 1811 an English physiologist, a man of profound sagacity, after having 

 long meditated on this vast network of nerves, Avhose complication seems incx- 

 tricahle, published a pamphlet of a few pages, in which, according to his own 

 expression, he submitted to Ms friends his views and ideas. 



The principle with which everything in this tractate connects itself is, that 

 whenever two or more nerves proceed to the same part, it is not for the purpose 

 of repeating, of reduplicating therein the same action, but to indue it respect- 

 ively with a different function. For example, two nerves proceed to the face; 

 the one is for the voluntary movement, the other for the respiratory movement. 

 The tongue receives three nerves : one for the movement of deglutition, another 

 for the voluntary movement, a third for the sense of taste. Each nerve, there- 

 fore, has its determinate office, its precise mission. But it remained to clear up 

 a point still more difficult. The greater part of the nerves, all those, for instance, 

 of the spinal marrow, are at the same time motive and sensitive. Now, how can 

 this be? How shall two functions coexist in a single organ? It was at this 

 point that, by an inspiration of genius, 0. Bell conceived the idea of the duality 

 of each nerve, each being composed of two, the one for sensation, the other for 

 movement ; in this we have the explanation why each nerve has two roots, and 

 in each root, taken separately, is seen the primitive, the simple, the distinct 

 nerve. M. Bell, therefore, submits each root to experiment; he obtains, as re- 

 gards one of the two, a clear and precise result, and from the property manifested 

 oy this one he infers the property which resides in the other. 



This experiment, an ever-memorable though in/'.omplete one, was the first step. 

 Ten years later, M. Magendie read to the Academy a memoir, in which he an- 

 nounced that having divided the anterior voot of a nerve he had abolished only 

 Tnovemcnt, and that having divided the posterior root he had abolished only 

 sensation. In this he had simply completed the experimeirt of M. Bell, but this 

 completion was in itself a new and important advance ; for here nothing was left 

 to deduction, but all was positive ; the experimental demonstration was perfect. 

 It seems that, in England, all the import of the discovery to which the name of 

 Bell had been first attached, was only comprehended when it became known 

 there how much admiration was excited on this side of the channel by the subtle 

 investigations of Magendie. 



The impression produced by the rare sagacity of our dexterous experimentalist 

 was still in the ascendant when- he himself, by one of those abrupt changes to 

 which he was but too subject, gave a complete denial to his previous results. 

 On this occasion the vacillation was not without excuse; in an inquiry so deli- 

 cate, the further the exploration was carried the more complex became the 

 enigma. 



M. Magendie, an experimentalist far more practiced than M. Bell, could not 

 multiply his researches without perceiving that the root recognized as motive, 

 that is to say, the anterior one, yielded signs oi sensibility. Whence did it derive 

 that sensibility ? Unsparing towards himself, fully as much as towards others, 

 M. Magendie passed twenty years of his life in seeking the solution of this new 

 problem ; and we may say to-day, to the honor of his memory, and before this 

 Academy which so greatly applauded it, that he found that solution. 



criminated by Herophilus and Eudemus, the first, after Hippocrates, who accurately de- 

 scribed the anatomy of the nerves, and who thus have left no slight occasion of perplexity 

 to physicians in icgard to the fact that, through palsy of the nerves, sometimes the sense 

 only, sometimes the motion, and sometimes both together, are abolished. "Wherefore, when 

 motion is lost, this we mostly call palsy (risolutio) of the nerves ; but where the sense of 

 certain parts has perished, we are accustomed to say rather that such part is devoid of sensa- 

 tion, although there are some who call this affection a palsy of the sense. We leave to each, 

 however, to apply these names at his pleasure. Physicians lose sight of the fact that 

 the nerves distributed through the skin of the hand, and by which the faculty of sensa- 

 tion is conveyed to it, have their 'appropriate roots, and that there are other roots of the 

 nerves by which the muscles are put in motion." Galen, De Loc. Affect, p. 21, apud Juntas, 

 Venice 1597 



