On the Agency of Nerves. 277 



inasmuch as they afford examples of secretion going on, where 

 this nervous influence either must have been cut off, or could 

 never have been applied. 



It appears, even from some of Dr. Philip's statements (to 

 which I confess I did not sufficiently advert in my former paper), 

 that in his experiments, the alteration made on the secretion of 

 the stomach, by cutting the eighth pair of nerves, was in quality 

 onl^y not in quantity. The secretion goes on, but its chemical 

 composition appears to be so altered, that it does not act, as 

 formerly, on the food. The secretion on the membrane lining 

 the bronchia, instead of being diminished, is very considerably 

 increased by this operation. Whether its composition is altered 

 or not, does not appear. In like manner, Bichat found*, on 

 dividing the nerves supplying the testis of a dog (the only 

 gland, he affirms, on which this experiment can be fairly tried), 

 that the gland inflamed and swppuratedy — a process allowed by 

 the best pathologists to be strictly analogous to secretion. 



The state of the fact, therefore, is, that a material change is 

 produced on the composition of the secretion of the stomach by 

 the division of the eighth pair of nerves ; but that in this, and 

 in other instances, secretion (that is, the formation out of tlxe 

 blood of a substance not previously contained in it) goes on, not- 

 withstanding that division. From this fact Dr. Philip concludes, 

 ^rs^,that secretion in general depends on an influence transmitted 

 by the nerves to the secreting organ ; and, secondly ^ that, after 

 the division of the nerves of that organ, a part of the nervous 

 influence, previously transmitted from the brain, or spinal mar- 

 row, remains in the nerves below the division, and supports the 

 degree of secretion that continues in these circumstances. 



All this he appears to consider^not merely as a plausible ex- 

 planation, but as dinecessai-y consequence of the fact just stated; 

 and certainly, if it be not proved by this fact, I know of no 

 other by which it is proved. But to me it appears, not only 

 that he has not adduced, as he supposes, an experimentum cruets 

 in favour of the doctrine of the dependence of secretion on 



* ^Imi^ Genet'. T. 4, p. C04. 



