ouch, about six to eight inches long and two inches in diameter, has
become distorted down into a narrow, contracted end portion, about a
quarter of an inch in diameter, and a distended first portion, for all
the world like a corncob pipe with a crooked stem and an unusually large
bowl. And behold--the modern _appendix vermiformis_, with all its fatal
possibilities!

If we want something distinctly human to be proud of, we may take the
appendix, for man is the only animal that has this in its perfection. A
somewhat similarly shriveled last four inches of the _caecum_ is found in
the anthropoid apes and in the wombat, a burrowing marsupial of
Australia. In some of the monkeys, and in certain rodents like the
guinea-pig, a curious imitation appendix is found, which consists simply
of a contracted last four or five inches of the _caecum_, which, however,
on distention with air, is found to relax and expand until of the same
size as the rest of the gut.

The most strikingly and distinctly human thing about us is not our
brain, but our appendix. And, while recognizing its power for mischief,
it is only fair to remember that it is an incident and a mark of
progress, of difficulties overcome, of dangers survived. In all
probability, it was our change to a more carnivorous diet, and
consequently predatory habits, which enabled our ancestors to step out
from the ruck of the "_Bandar-Log_," the Monkey Peoples. An increase in
carnivorousness must have been a powerful help to our survival, both by
widening our range of diet, so that we could live and thrive on anything
and everything we could get our hands on, and by inspiring greater
respect in the bosoms of our enemies. Let us therefore respect the
appendix as a mark and sign of historic progress and triumph, even
while recognizing to the full its unfortunate capabilities for mischief.

But what has this ancient history to do with us in the twentieth
century? Much in every way. First, because it furnishes the physical
basis of our troubles; and second, and most important, because, like
other history, it is not merely repeating itself, but continuing. This
process of shriveling on the part of the appendix is not ancient history
at all, but exceedingly modern; indeed, it is still going on in our
bodies, unless we are over sixty-five years of age.

In the first place, we have actually passed through two-thirds of this
process in our own individual experience.

At the first appe