MEMOIR OF MAGENDIE. 115 



disturbance caused by the experiment. It then became possible to verify in the 

 clearest manner the sensibility of the peripheric ends of the anterior roots of the 

 fourth and fifth lumbars. The peripheric ends of the branches of the facial nerve 

 also evinced sensibility in tho most distinct mannei*. This recurrent sensibility 

 of the anterior lumbar roots and of the facial nerve was prolonged with equal 

 intensity during the whole day. Four hoiu-s after the experiment, the acute 

 sensibility of the peripheric ends of the lumbar roots and of the facial nerve was 

 still found to exist in the most lively activity, and continued to do so even the 

 next day, (twenty-four hours after the experiment,) notwithstanding the com- 

 mencement of swelling and suppuration of the wounds. Second cxprrinient : 

 In a lively and healthy dog, of medium size and from four to five months old, 

 the lumbar medulla was laid bare on the right side to the extent of a single 

 vertebra, the pair exposed being the fifth lumbar nerves. The anterior root of 

 this nervous pair being lightly disengaged, was pricked and found to be evidently 

 sensible. After this sensibility had been verified at several intervals, the anterior 

 root was cut, and the peripheric end found to retain its sensibility, while the end 

 adjoining the marrow had become completely insensible. The wound of the 

 back was then sewed up. On being examined anew five hours afterwards, 

 nothing had changed ; the sensibility of the peripheric end of the anterior root 

 remained in full activity, and the complete insensibility of the central end was 

 persistent. The corresponding posterior root was now cut, and pain and agita- 

 tion were apparent. But the recurrent sensibility of the anterior root immediately 

 disappeared ; so that of the four nervous extremities resulting from the division 

 of the anterior and posterior roots, there was but one, the central end of the 

 posterior root, in which sensibility continued to be lively. Twenty-two hours 

 after the experiment the wound had become fetid, suppuration having com- 

 menced ; yet the exquisite sensibility of the central end of the posterior root, 

 ard the complete insensibility of the three other ends, could be distinctly verified. 

 Third and fourth experiments : From these, made on animals from four to six 

 months old, the same facts residt, namely : sensibility en retour of the anterior 

 roots, and of the facial. Sometimes at the very moment of the experiment thi.> 

 recun-eut sensibility is nol quite evident, and it is then necessary to wait some 

 instants for the animal to recover a little from the disturbance caused by the 

 pain of the experiment. It was then ascertained that the section of the posterior 

 root caused the recurrent sensibility of the anterior root constantly to disappear, 

 and this even eighteen hours after the operation. It was seen also that the 

 sensibility en retour of the anterior root having been once destroyed reappeared 

 no more, however long a time it might be waited for. Fifth experiment: I\rade 

 on an adult dog, with the same constant results of the recurrent sensibility persist- 

 ing till the next day; (the root was attached with a thread.) Sixth experiment : 

 Two lumbar vertebrae of an adult dog were laid bare, and it was found, after 

 the animal had been left at rest for some ten minutes, that the anterior roots 

 were sensible ; the animal was then bled, and this sensibility en retour disap- 

 peared, while the sensibility of the posterior roots was always persistent." 



Conclusion. — I have repeated all the experiments of M. Magendie on the 

 recurrent sensibility, as well alone as in company with M. Bernard, and have 

 caused them to be repeated perhaps twenty times in my laboratory by my aide- 

 naturalists. Dr. Philipeaux, whose skilful and practiced hand may justly be re- 

 ^garded as an additional guarantee. I have thus verified, even to the smallest 

 details, all that M. Magendie had observed, and all that he has recounted in his 

 Note of 1S47. To reproduce these experiments with success, care must be taken 

 to practice them under the requisite conditions : First, to open the rachis but on 

 one side. Second, to expose the roots of but one or, at most, of two nerves. 

 Third, not to explore the roots until the lapse of five or six hours after the first 

 operation, in order that the animal may have recovered from the disturbance at' 



