1819.) and on the Blood in general. 15 
others were reduced to a mere husk, while others again were in 
various states between these two extremes. The whole contents 
of the stomach exhibited decidedly acid . properties ; but the 
litmus paper recovered its blue colour again almost mstantly 
on exposure to the air. They coagulated milk completely, but 
yielded no trace of an albuminous principle. 
Phenomena of Digestion in the Tench and Mackerel.—The 
contents of the stomach and upper intestines of the tench were 
examined immediately after death. As, however, the animal had 
been previously kept for a considerable time im an unnatural 
state, the phenomena observed were not so satisfactory as could 
have been wished. The contents of the stomach and upper 
portion of the intestines consisted of little more than a yellowish 
glairy fluid, which seemed to be bile; and the small portion of 
alimentary matter present appeared to be unnatural, and little 
capable of being acted upon by the digestive powers. No traces 
of an albuminous principle were, therefore, discoverable, nor 
indeed could be expected to exist in the stomach, or the upper 
portions of the alimentary canal. The mackerel, whose digestive 
organs were the subject of examination, had just arrived from 
the coast where it had been caught the day before. The stomach 
was nearly filled with a whitish grumous mass, in which the 
undigested bony remains of some small fish were distinctly 
visible. This mass very faintly reddened litmus; and, by the 
assistance of heat, coagulated milk. It underwent a sort of 
partial coagulation by the aéetic and other acids, especially when 
eat was applied; but no traces of albuminous matter could be 
erceived in it. 
Phenomena of Chymification—The examinations of chyme 
have not been numerous. Dr. Marcet has published a brief 
account of the chyme of the turkey. I have myself examined 
the chymes of several different animals : some of the most im- 
portant of these examinations I shall detail at length; the 
results of others will be only mentioned. In these examinations 
my chief object has been to ascertain if the chyme exhibited any 
traces of the albuminous contents of the blood. 
Comparative Examination of the Contents of the Duodena of 
two Dogs, one of which had been fed on vegetable Food, the other - 
on animal Food ouly.*—The chymous mass from vegetable food 
(principally bread) was composed of a semifluid, opaque, yellow- 
ish white part, containing another portion of a similar colour, but 
firmer consistence, mixed with it. Its specific gravity was 1-056. 
It showed no traces of a free acid, or alkali; but coagulated milk 
completely, when assisted by a gentle heat. 
* For the opportunity of making these examinations, as well as those of the 
chyle afterwards related, 1 am indebted to the kindness of Mr. Astley Cooper, 
who, wishing to ascertain the properties of these substances, when preparing his 
lectures for the Royal College of Surgeons, upwards of four years ago, obliging!y 
furnished me with the materials for making the requisite experiments, 
