arance of the _caecum_, or blind pouch, in our prenatal
life, it is of the same calibre as the rest of the intestine, and of
uniform size from base to tip. About three weeks later the tip begins to
shrivel, and from this on the process steadily continues, until at birth
it has contracted to about one-fifteenth of the bulk of the _caecum_. But
the process doesn't stop here, though its progress is slower. By about
the fifth year of life the stem of the caeco-appendix pipe has diminished
to about one-thirtieth of the size of the bowl, which is the proportion
that it maintains practically throughout the rest of adult life. For a
long time we concluded that the process was here finished, and that the
appendix underwent no further spontaneous changes during life; but,
after appendicitis became clearly recognized, a more careful study was
made of the condition of the appendix in bodies coming to the
post-mortem table, dead of other diseases, at all ages of life. This
quickly revealed an extraordinary and most significant fact, that, while
the appendix was no longer decreasing in apparent size, its internal
capacity or calibre was still diminishing, and at such a rate that by
the thirty-fifth year it had contracted down so as to become cut off
from the cavity of the _caecum_ in about twenty-five to thirty per cent
of all individuals. By the forty-fifth year, according to the anatomist
Ribbert (who has made the most extensive study of the subject), nearly
fifty per cent of all appendices are found to be cut off, and by the
sixty-fifth year nearly seventy per cent.

This explains at once why appendicitis is so emphatically a disease of
young life, the largest number of cases occurring before the
twenty-fifth year (fifty per cent of all cases occur between ten and
thirty years of age), and becoming distinctly rarer after the
thirty-fifth, only about twenty per cent occurring after this age. As
soon as the cavity of the appendix is cut off from that of the
intestine, it is of course obvious that infectious or other irritating
materials can no longer enter its cavity to cause trouble, although, of
course, it is still subject to accidents due to kinks, or twists, or
interference with its blood-supply; but these are not so dangerous,
providing there be no infectious germs present.

Here, then, we have a clear and adequate physical basis for
appendicitis. A small, twisted, shriveling spur or side twig of the
intestine, opening from a