72 NERVOUS SYSTEM. 



to have been distinctly indicated in the text ; but in a reprint 

 of the paper of 1821, in 1830, there is no indication to the 

 reader that any change had been made from the original, 

 though every expression bearing upon the question is made 

 to correspond with the information derived from the discov- 

 eries of Magendie. 1 This is a subject which we have no 

 desire to pursue farther than is necessary to vindicate the 



1 CHARLES BELL, The Nervous System of the Human Body, embracing the 

 Papers delivered to the Royal Society on the Subject of the Nerves, London, 1830, 

 p. 55, et seq. 



In the appendix to the work on the Nervous System, published in 1844, 

 the claim to the discovery of the distinct functions of the anterior and posterior 

 roots of the spinal nerves is distinctly made by Sir Charles Bell, who refers to 

 the experiments detailed in the pamphlet of 1811. It will be seen by the fol- 

 lowing extract, as compared with the extracts which we have made from the 

 pamphlet, that the statements by Sir Charles Bell as to what wa's contained in 

 this pamphlet are incorrect and calculated to convey an erroneous idea with 

 regard to the nature of the observations, printed in 1811, but inaccessible, and 

 of the deductions made at that time. 



" Long before this (1811) I wrote a little book, put it into the hands of my 

 friends, and had it printed and distributed ; it contained (excuse me in saying it) 

 this great principle that a nerve, whatever its nature may be, cannot perform 

 two functions at once pit cannot convey sensation inward to the sensorium at 

 the same moment that it carries outward a mandate of the will to the muscles, 

 whether it be through the means of a fluid, or an ether, or a vibration, or what 

 you will, that it performs its function. Two vibrations cannot run counter 

 through the same fibre, and at the same instant ; two undulations cannot go in 

 different directions through the same tube at the same moment ; and therefore I 

 conceived that the nerves must be different in their kind. This led me to ex- 

 periment upon the nerves of the spine ; for I said : ' Where shall I 1 be able to find 

 a nerve with the roots separated? Where shall I be able to distinguish the 

 properties of a compound nerve ? By experimenting upon the separate roots 

 of the spinal nerves. ' So, then, taking a fine instrument, the point of a needle, 

 and drawing it first along one set of roots, and then along the other, I found 

 that, as I touched one set the anterior roots it was like touching the key of 

 a piano-forte, all the cords, as it were the muscles were in vibration ; and 

 when I touched the other there was pain and struggling. That would not do ; 

 the animal being alive to sensation, there was confusion here ; and therefore I 

 struck the animal on the head, and then I made my experiments clearly ; by 

 which it was shewn, that the roots of these nerves were of different qualities, 

 one obviously bestowing motion ; and, by inference, the other bestowing scnsi- 

 bility" (The Nervous System, etc., London, 1844, p. 285). 



