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1X. On the Formation of Fat in the Intestines of living Ani- 
mals. By Sir Everarp Home, Bart. Presented by the 
Sociely for promoting the Knowiedge of Animal Chemistry *. 
a HE investigation of the digestive organs of different animals, 
in which I have been engaged for many years, has led me im- 
perceptibly into an inquiry respecting the ab a uses of the 
lower portion of the intestines in birds and quadrupeds. 
. The first thing that attracted my notice more particularly to 
hid subject, was finding that, in all animals whose stomachs are 
made up of a great variety of parts for the purpose of cecono- 
mizing the food, the colon has a greater extent of surface, and 
the course of the canal is so disposed that its contents must be 
a long time in their passage through it. This circumstance led 
me to believe that the food, after the chyle is formed and se- 
parated from it, undergoes in the lower intestines some changes, 
by which a secondary kind of nourishment is extracted from it. 
This opinion was much strengthened, by finding that the 
colon of the casuary from Java is only one foot long, and each 
of the ceca which are appendages to it, only six inches long, 
and a quarter of an inch in diameter; while the African ostrich 
has the colon forty-five feet, and each of the ceca two feet nine 
inches in length, and at the widest part three inches in diameter : 
besides which, both the colon and ceca have very broad valvule 
conuiventes not met with in the casuary from Java. This won- 
derful difference, for it is more than fifty to one, can only be ex- 
plained by the lusuriancy of Java being so great, that this bird 
might destroy its health by over- -feedin ig, had no guard been 
furnished by nature. 
This guard is, the food passing through the intestines with 
so much facility, and in so short a time, ” that, however much 
the bird may eat, only the necessary quantity of nourishment is 
carried into the constitution ; ; but in the African ostrich, the food 
is retained in the extensive colon till every thing nutritious is ex- 
tracted. In all ruminating animals, the colon is of great length, 
is fixed in its course, which is very intricate, and varies in every 
different genus; so that we cannot doubt of some particular 
process being carried on in it. 
The process which the contents of the eclon undergo, is quite 
distinct from any thing carried on in the other intestines, since 
they entirely change their appearance and smell; and there is 
commonly a valve to prevent any part of them, even the gases 
evolved, from being carried up into the small intestines, 
The peculiar smell of the feces, which borders so closely on 
* From the Philosophical Transactions for 1813, part ii. 
C2 that 
