5§4 
Animals and their Diet. 
[October, 
We now see that the zoophagous and phytophagous forms 
of animal life are not separated from each other by any 
sharply-marked characters, but are connected by a multitude 
of creatures intermediate in their organisation, and conse- 
quently adapted for a mixed diet. We see that animal food 
is regularly, and in considerable proportion, eaten by species 
not constructed on the typically zoophagous type as wit- 
nessed in the tiger or the polecat. Yet such species as we 
may infer from the very faCt of their existence are not 
thereby injured. 
We know that the great mass of vegetables, especially the 
leaves, stalks, and even the roots and the fleshy part of the 
fruits, are less nutritious than is ordinary animal matter. 
To this rule the seeds of a number of plants, such as the 
legumens and the various kinds of grain, form an exception, 
though even here it would appear that a part of the nitro- 
genous matter is not present in a state suitable for assimila- 
tion. In other words, it exists not entirely in an albumenoid 
but in an amidic state. Hence we must conclude that an 
animal which is to exist entirely upon a vegetable diet must 
have larger digestive organs, so as to operate upon the 
greatest quantity of matter at once. On the other hand, 
purely zoophagous species require, or at least can exist with, 
a smaller and simpler digestive apparatus. We may go a 
step further: of all nutriment the poorest — i.e ., that which 
contains the smallest quantity of blood-forming matter — 
consists of leaves and stalks. Accordingly the Ruminants, 
which feed upon leaves and stalks, have the largest and 
most complicated stomachs. In the Solidungula, of which 
the horse and the ass are typical specimens, the diet is the 
same as that of the Ruminants, but the stomach is simple, 
and digestion is in consequence far less perfectly performed, 
as an inspection of the respective excrements of the horse 
and the ox will readily show. May it not be that we have 
here the reason why the Solidungula as a sub-order are so 
far less rich in forms and less widely distributed ? We 
come now to such animals as the swine. Here the divisions 
of the stomach occurring in the Ruminants are but faintly 
marked out, to suit a richer diet, composed largely of roots 
mixed with no inconsiderable proportion of animal matter. 
A step further we find the apes feeding on fruits and 
nuts, with the addition of eggs, larvae, &c. Here the 
stomach is simple, and the whole digestive apparatus 
lighter in proportion to the entire body than that of the 
swine. Lastly, in the true Carnivora, where the diet is 
most concentrated, we find the digestive canal shortest, 
