Mr, Brodie on the injiuence of the Nerves ^ &c. 103 
But this, with respect to the greater number of the glands, is 
an experiment impossible to perform; and, with respect to 
others, can not be executed without so much disturbance and 
injury to the other parts, as must render it extremely difficult 
to arrive at any positive results. Perhaps in future investi- 
gations, some circumstances may arise, which will enable us to 
determine more satisfactorily this important physiological ques- 
tion. In the mean time, as the labours of physiologists have 
hitherto contributed so little to this purpose, any facts that 
tend to its elucidation may deserve to be recorded, and I am 
therefore induced to lay before the Society the following ex- 
periments, which afford one example of a secretion being 
dependent on the influence of the nerves. 
The stomach derives its nerves principally from those of 
the eighth pair, or the par vagum ; and the same nerves, as 
they assist in the formation of the semiluitar ganglions, con- 
tribute to the supply of the rest of the alimentary canal, par- 
ticularly of the small intestines. In an inquiry which I had 
formerly instituted, respecting the functions of the stomach, 
I divided these nerves in the neck of a dog, for the purpose 
of ascertaining the influence which they possess on the secre- 
tion of the gastric juice; but I was disappointed in my expec- 
tation, since the animals always died, in consequence of the 
disturbed state of the respiration, which the injury of the 
nerves occasioned, before there was an opportunity of ascer- 
taining the effect produced on the process of digestion. 
I had formerly ascertained, that in a dog poisoned by arsenic, 
there is a copious secretion of mucous and watery fluid from 
the mucous membrane of the stomach and intestines, whicli 
are in consequence found after death completely and preter- 
