MOTOR AND SENSORY NERVES. 75 



The experiments in which the anterior roots were di- 

 vided were no less striking : 



"As in the preceding experiments, I only made the 

 division upon one side, in order to have a term of compari- 

 son. One can conceive with what curiosity I followed the 

 effects of this division ; they were not at all doubtful, the 

 limb was completely motionless and flaccid, while it pre- 

 served a marked sensibility. Finally, that nothing should 

 be neglected, I divided at the same time the anterior and 

 the posterior roots ; then followed absolute loss of sensation 

 and of motion." 1 



Prom these experiments Magendie drew the following 

 conclusions : 



" I am following out my researches, and will give a more 

 detailed account of them in the following number ; it is suf- 

 ficient for me to be able to announce at present as positive, 

 that the anterior and the posterior roots of the nerves which 

 arise from the spinal cord have different functions, that the 

 posterior seem more particularly devoted to sensibility, 

 while the anterior seem more especially connected with 

 motion." 2 



In the second note, published in the same volume of the 

 Joui-nal de physiologie^ Magendie exposed and irritated the 

 two roots of the nerves, with the following results : 



" I commenced by examining in this regard the poste- 

 rior roots, or the nerves of sensation. The following is the 

 result which I observed : on pinching, pulling, or pricking 

 these roots, the animal manifested pain ; but this was not to 

 be compared as regards intensity with that which was 'de- 

 veloped if the spinal cord were touched, even lightly, at 

 the point of origin of the roots. Nearly every time that 

 the posterior roots were thus stimulated, contractions were 

 produced in the muscles to which the nerves were distrib- 

 uted ; these contractions, however, are not well marked, 

 and are infinitely more feeble than when the cord itself is 



1 Ibid., p. 278. ' Ibid., p. 279. 



