a proof of the dependence of the nutritive operations upon 

 nervous agency. I think the following experiments give evi- 

 dence against that doctrine. I have divided the sciatic nerve 

 in a number of rabbits and guinea-pigs, and placed some of them 

 at liberty in a room with a paved floor, whilst I confined others 

 in a box, the bottom of which was thickly covered with bran, hay 

 and old clothes. In a fortnight, the former set exhibited an ob- 

 viously disordered action in the paralysed limbs ; the claws were 

 entirely lost ; the extremities of the feet were swollen, and the 

 exposed tissues were red, engorged, and covered with fleshy gra- 

 nulations. At the end of a month, these alterations were more 

 decided, and necrosis had supervened in the denuded bones. On 

 the other hand in the animals confined in the boxes, no such 

 injuries had accrued ; and although some of them have been 

 kept living for four, five and even six months after the division 

 of the sciatic nerve, no alteration whatever has appeared in the 

 palsied limbs except atrophy. In these cases a portion of the 

 nerve had been cut off, so that reunion was nearly impossible 

 and did not take place. 



Experiments made on pigeons have given the same results. 



It is obvious from these experiments that the pathological 

 changes which occur after the section of the sciatic nerve do not 

 proceed directly from the absence of nervous action, but that 

 they are consequent upon the friction and continual compression 

 to which the paralysed limbs are subject, against a hard soil, 

 owing to the inability of the animal to feel or avoid it. 



In similar experiments made on frogs, I found that no altera- 

 tion took place, except when water penetrated through the 

 wound, under the skin, and between the muscles.* 



2. With the help of an eminent micrographer (Dr. Lebert), I 

 have made researches on the influences produced on the capillary 

 circulation in consequence of the section of all the nerves (sym- 

 pathetic and cerebro-spinal nerves) in the legs of a number of 

 frogs. We have found no appearance of trouble in the capillary 

 circulation, neither in an hour, nor in three or four days after the 

 division of the nerves. 



3. When resection of a long portion of one of the sciatic 

 and the crural nerves is made on a very young rabbit, guinea- 



* See Gaz. Med. de Paris. 1849 ; t. 4, p. 880. 



