138 
DR. PHILIP ON DIGESTION. 
nearly completed before the food is actually in contact with the stomach, as 
may be seen by inspecting that of an animal killed a few hours after a meal ; 
and consequently is not detained when in contact with it. There is therefore 
a continual motion of the food in contact with its surface towards the pylorus, 
and the less digested part is continually approaching its surface. 
It follows then that a failure of the function of the stomach may arise either 
from a proper gastric juice not being supplied, or the muscular power of the 
stomach failing to carry onward the digested part, and thus regularly to pre- 
sent to the stomach a new surface of food to be acted upon by that juice. It 
further appeared, that for the first of these purposes the power of the nervous 
system is necessary, the secretion of gastric juice failing as soon as the stomach 
is deprived of any considerable part of this power ; but that the nervous power 
is not necessary for the other, the muscular power of the stomach still carrying 
on towards the pylorus any digested food which happens to be in it, or any 
food which had been acted upon by gastric juice which happened to be in it at 
the time, however much its nervous power be impaired ; and this office is, as 
far as we can see, as readily performed as when the nervous power of the 
organ is entire. 
The muscular fibres of the stomach therefore are stimulated by its contents, 
in the same way as those of the heart by the blood, the usual action of both 
being wholly independent of the nervous system, an inference confirmed by 
many other experiments beside those here referred to. 
I have, as appears from the papers which the Society have done me the 
honour to publish, attempted to go a step further, and to show experimentally 
that the office of the nervous power in preparing the gastric juice, may be cor- 
rectly imitated by exposing the living stomach to the influence of a voltaic 
pile after the supply of nervous power is interrupted. Those who were at first 
inclined to doubt this fact, have since publicly acknowledged, on witnessing 
the experiments, that the digestive process of the stomach supported by gal- 
vanism, is, as far as we can see, as perfect as that supported by the nervous 
power itself. 
It is therefore evident that in the formation of the gastric juice, a chemical 
power can be substituted for that of the nervous system. I do not mean that, 
strictly speaking, its formation is to be regarded as a mere chemical process, 
