70 FARM ANIMALS 
age purposes, but in them, particularly in the smaller, the 
real digestive act—the absorption of the nutriment in the 
food by the blood—takes place. Up to this point, al- 
though fluids have been at 
work, there has been little if 
any active absorption of the 
nutrients. The food up to 
now is, in a sense, outside 
the body, and there is no en- 
trance or opening for it into 
the body save through the 
cells that line the intestinal 
Loon. BLAS A section of the digestive tract. 
pulis shows, blood plasma passisx 40. Food absorption — 
There are no body gates that 
open and close, and through which the digested materials 
can be delivered into the body. Food is admitted by ab- 
sorption. Ina way similar to that by which soluble plant 
food is carried into the plant roots through the cell walls, 
so is the digested food, after it has been broken up and 
made soluble, absorbed through the cell walls of the in- 
testines into the blood. 
11. Villi cells—The digested food in the intestines is 
gathered in by villi cells. The mucous membrane lining 
the small intestines possesses highly differentiated struc- 
tures that appear as minute fingers. These tiny, hairlike 
projectiles reach into the intestinal mass for sugar, pep- 
tones and fatty acids, and transfer them through the cells 
into the absorbent vessels or lymphs that in turn empty 
the assimilated stores of food into larger and still larger 
vessels. This process continues until the whole of the 
nutritive fluid is collected in the circulatory system, later 
to become the very basis of the blood. 
12. From intestines to blood—When food is absorbed 
