ird of the tube
distends and sacculates out into a so-called _large intestine_, in which
the last remnants of nutritive material and of moisture are extracted
from the food-residues before they are discharged from the body. Just at
the junction of this large intestine with the small intestine, nature
took it into her head to develop a second pouch, a sort of copy of the
stomach. This pouch, from the fact that it ends in a blind sac, is known
as the _caecum_ (or "blind" pouch), and is apparently simply a means of
delaying the passage of the foodstuffs until all the nutriment and
moisture have been absorbed out of them for the service of the body.
Naturally, it has developed to the largest degree and size in those
animals which have lived upon the bulkiest and grassiest of foods, the
so-called _Herbivora_, or grass-eaters. In the _Carnivora_, or
flesh-eaters, it is usually small, and in one family, the bears,
entirely absent. This pouch is no mere figure of speech, as may be
gathered from the fact that in certain of the rodent _Herbivora_, like
the common guinea-pig, it may have a capacity equal to all of the rest
of the alimentary canal, and in the horse it will hold something like
four times as much as the stomach. Oddly enough, among the grass-eaters,
for some reason which we do not understand, it appears to occur in a
sort of inverse proportion to the stomach; those which have large,
sacculate, pouched stomachs, like the cow, sheep, and the ruminants
generally, having smaller _caeca_. In other _Herbivora_ with small
stomachs, like the rabbit and the horse, it develops greater size.

Our primitive ancestors were mixed feeders, and, though probably more
largely herbivorous than we are to-day, had a medium-sized _caecum_, and
maintained it up to the point at which the anthropoid apes began to
branch off from our family-tree. But at about this point, for some
reason, possibly connected with the increasing variety and improved
quality and concentration of the food, due to greater intelligence and
ability to obtain it, this large _caecum_ became unnecessary, and began
to shrivel.

Here, however, is where nature makes her first afterthought mistake.
Instead of allowing this pouch to contract and shrivel uniformly
throughout its entire length, she allowed the farther (or _distal_)
two-thirds of it to shrivel down at a much faster rate than the central
(or _proximal_) third; so that the once evenly distended sausage-shaped
p