82 NERVOUS SYSTEM. 



is now known as the recurrent sensibility of the anterior 

 roots, and to have communicated his views to Magendie ; ' 

 but the publications on the subject and the testimony of 

 Bernard, 2 who witnessed all the experiments in the labora- 

 tory of the College of France, as well as the observations of 

 Magendie, in 1822, leave no doubt that he was the first to 

 note the sensibility of these roots. 



The experimental facts with regard to the recurrent sen- 

 sibility are very simple. If the two roots of a spinal nerve 

 be exposed, and if the animal be allowed to recover, by a 

 few hours' repose, from the shock of the operation, irrita- 

 tion of the posterior root will produce pain and the general 

 movements incident to it, but no localized contractions of 

 muscles; and irritation of the anterior root will produce 

 contraction of certain muscles and a certain amount of pain, 

 always less, however, than the pain resulting from stimula- 

 tion of the posterior roots. If the anterior root be divided, 

 the end attached to the cord will be found completely insen- 

 sible, but the peripheral end will manifest the same sensibili- 

 ty as the undivided root ; showing that the sensory proper- 

 ties of the anterior roots are not derived from the cord. If 

 the posterior root be divided, the sensibility of the anterior 

 root is instantly abolished ; showing that the sensibility of 

 the anterior root is recurrent, being derived from the poste- 

 rior root through the periphery. With regard to these facts 

 there can be no doubt, and we ourselves verified them in a 

 series of experiments published in 1861. 3 Experiments have 

 simply demonstrated the fact that the recurrent sensibility 

 comes through the periphery, without actually showing any 

 recurrent fibres ; and division of a mixed nerve after the 

 nnion of the two roots deprives the anterior root of its scn- 



1 LONGET, Traite de physiologic, Paris, 1869, tome Hi., p. 115. 



2 BERNARD, Lemons sur la physiologic et la pathologic du syst&me nerveux, Paris, 

 1858, tome i., p. 35. 



3 FLINT, JR., Experiments on the Recurrent Sensibility of the Anterior Roots of 

 ffte Spinal Nerves. New Orleans Medical Times, 1861, p. 21, et seq. 



