MEMOIR OF MAGENDIE. 107 



APPENDIX I. 



ON THE DISCOVERY OF THE DISTINCT FUNCTIONS OF THE ROOTS OF THE 



NERVES. 



I. — M. Bell published, in 1811, a pamphlet, under tlie following title : Idea of 

 a New Anatomy of the Brain, suhmiited for the observations of his friends. In 

 this he first announces his ingenious idea that each nerve, which is both motive 

 and sensitive, is a double nerve, and secondly describes his experiment. In re- 

 gard to his idea of double nerves, or, as the author calls them, mixed nerves, he 

 says : " I have to offer reasons for believing that * * the nerves which we 

 trace in the body are not single nerves possessing various powers, but bundles 

 of different nerves, whose filaments are united for the convenience of distribu- 

 tion, but Avhich are distinct in office as they are in their origin from the brain." 

 (Bell : The Nervous System of the Human Body, &c.; 3d edition, Edinburgh, 1836, 

 p. 442.) He adds : " Considering that the spinal nerves have a double root, and 

 being of opinion that the properties of the nerves are derived from their connec- 

 tions with the parts of the brain, I thought that I had an opportunity of putting 

 my opinion to the test of experiment, and of proving at the same time that nerves 

 of different endowments were in the same cord and held together by the same 

 sheath." {Ibid, p. 443.) In stating his experiment, M.Bell says : " On laying 

 bare the roots of the spinal nerves, I found that I could cut across the posterior 

 fasciculus of nerves which took its origin from the posterior portion of the spinal 

 marrow without convulsing the muscles of the back ; but that on touching the 

 anterior fasciculus with the point of the knife, the muscles of the back were im- 

 mediately convulsed." [Ibid, p. 443.) 



We thus see what was done by Bell : first, it was he who first conceived that 

 each nerve might be double, or composed of two ; secondly, it was he who, be- 

 fore all other physiologists, directed experiment to the roots of the nerves ; thirdly, 

 from his experiment, however incomplete, he arrived at the conclusion of a dis- 

 tinct function for each root. All this was accomplished by M. Bell ten years 

 before the researches of M. Magendie, 



II. — The titles of Magendie to the important discovery are distributable into 

 two series : by the first he completed the labors of Bell ; by the second he dis- 

 covered the recurrent sensibility. I shall begin by reproducing entire the first 

 " Note " of M. Magendie, and it will be seen how felicitous was his insight on 

 this first attempt. His first introspection was in fact always the surest. 



Experiments on the functions of the roots of the rachidian nerves, hj M. Ma- 

 gendie ; 22d July, 1822 : " I had long desired to make an experiment in cutting, 

 in some animal, the posterior roots of the nerves which spring from the spinal 

 marrow. I had several times attempted it without succeeding, on account of the 

 diflBculty of opening the vertebral canal without injuring the medulla, and con- 

 sequently destroying or at least sorely wounding the animal. Last month, a 

 litter of eight pups, six weeks old, was brought to my laboratory, and these 

 seemed well suited for a renewal of the attempt to open the vertebral canal. lu 

 effect, I was able, by the use of a very sharp scalpel, and so to say at a single 

 stroke, to lay bare the posterior half of the spinal marrow surrounded by its 

 envelopes. To have this organ almost naked, it only remained for me to cut the 

 dura-mater which encloses it, and this was done with facility ; I had then before 

 my eyes the posterior roots of the lumbar and the sacral pairs, and by raising 

 them successively with the blades of the small scissors I could cut them on one 

 side, while the marrow remained untouched. I knew not what would be the re- 

 sult of this attempt ; but I reunited the wound by a suture of the skin and ob- 

 served the animal. I at first thought the member corresponding to the nerves 



