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certain net results. We find it possible to secure such a net 
result by various mixtures, and some of them are much more 
economical at certain times than at others; so that the facts 
stated become the basis for an important branch of economics, 
Our discussion thus far has dealt only with the actual nutritive 
constituents in the food, as determined by chemical examination. 
We must next consider that this calculation does not necessarily 
give us a correct idea, nor even an approximate idea, of the ben- 
efit derived by the system from consuming the food under con- 
sideration, In the case of animal foods it usually does so, at 
least approximately, but not in that of vegetable foods, and this 
brings us to the first general distinction between the two classes. 
In animal foods the nutrients are mostly conditioned for imme- 
diate digestion when they reach the proper place in the human 
body ; in the vegetable foods most of them are not so. In both 
cases the principal nutrients are enclosed, in minute particles, in 
cavities enclosed by membranes. These membranes must be 
roken up or dissolved off, so as to free the contents, before the 
material. Albuminous material is chiefly digested in the stomach, 
so the membranes enclosing the animal nutrients are there dis- 
solved and the contents freed. Some of these contents are 
adapted to stomach digestion and the stomach juices at once 
attack them and perform this portion of the work. The others 
are passed on into the intestine for digestion later. Cellulose, on 
the other hand, is chiefly digested in the intestine, partially, 
slowly and with difficulty in the stomach. Part of the substance 
enclosed by the cellulose walls of vegetables properly require 
stomach digestion, but this is prevented, as stated, by the cellu- 
lose walls. It has, therefore, to be passed on into the intestine 
Digestion is prolongéd, laborious and commonly imperfect, and 
fermentation is very likely to occur. 
From these conditions results one of the fundamental facts upon 
which the discussion of vegetarianism must be based ; that vege- 
table foods require a different line of treatment from animal foods. 
