DR. PHILIP ON DIGESTION. 
141 
They also err in supposing that the muscular fibres of the stomach can be 
excited by irritating the eighth pair of nerves in the way that a muscle of volun- 
tary motion may be excited through its nerves. The digested food is the 
natural stimulus of the muscular fibres of the stomach in its usual function, 
as the nervous power is of the muscles of voluntary motion in theirs ; and we 
cannot through the nerves excite the former as we do the latter class of 
muscles. The muscular action of the stomach resembles that of other hollow 
muscles, in being excited by its contents. 
The mechanical irritation employed by those gentlemen, in endeavouring to 
excite the digestive process after a portion of the eighth pair of nerves had been 
removed, was that of a thread attached to the cut extremities of the lower por- 
tions of the eighth pair of nerves and fastened to the neighbouring muscles, by 
which the motions of respiration kept the part in a state of constant irritation. 
In my Treatise on the Vital Functions, a similar experiment is related, in 
which the cut extremity of the lower portions of the nerves was fastened to a 
thread tied round the neck of the animal, by which it was in like manner kept 
in a state of constant mechanical irritation; yet in the stomachs of the animals 
after they had lived more than twenty hours, — for the experiment was made 
more than once, — nothing but undigested food was found. This experiment, 
with some others connected with it, was made publicly in the rooms of the 
Royal Institution ; and all who felt an interest in the subject admitted to see 
the results, nor was there one who expressed a doubt respecting them. 
As, however, in the experiments just mentioned the position of the nerves 
was more disturbed, and the thread was not applied as in the experiments to 
which I have referred, Mr. Cutler, at my request, was so good as to make the 
following experiment. — Three rabbits, after a fast of the same duration, were 
fed in the same way. In two of them a portion of each of the eighth pair of 
nerves was removed. The third rabbit was left undisturbed. In one of those 
in which the portions of nerve were removed, the cut end of the lower part of 
the nerves was by means of a bit of thread fastened to the neighbouring 
muscles, as in the experiment referred to. This rabbit died in ten hours, at 
which time the others were killed in the usual way. 
Mr. Cutler then took out the stomachs of all of them, slit them open, and 
laid them on the same plate ; and Mr. Brodie was requested to examine and 
