a "knot," as it is
sometimes called, is formed. No possible instrument can reach it except
by cutting the body outright, but the action of cold is so powerful in
contracting the tube that the "loop," as it is also called, is drawn
out, and the right state of things is produced. It is important to
remark that there are glands near the lower bowel that swell and form
tumours. The cold applications reduce these very speedily to their
usual size, and if their swelling is an obstruction, it is soon
removed. But it is the lock in the tube itself that is the real malady
of which so many die, and with which so many more narrowly escape.

The trouble is best avoided by attention to the regular action of the
bowels. It arises from great irregularity in that action.

Bowels, Reversed.--_See_ Bowels, Locking of, above.

Brain Exercise.--Proper exercise for the brain is most important. But
this is not to be found in that kind of severe mental labour which is
sometimes mistaken for it. Children at play have genuine brain
exercise. So has a man at what is called a "hobby," such as
photography, golf, or cycling. The child at school, the man in his
office, are not at exercise, but at wearing work. This distinction is
most important. Exercise, again, is not found in careless dreaming, but
in some form of "play" which calls for steady, but almost unconscious,
and altogether enjoyable thinking. Books sometimes furnish this, when
they lift the mind as far as possible out of its usual track, and
produce only pleasant thoughts. Tragedies, novels which end miserably,
or which are pessimistic, should all be avoided. Perhaps some easy
science or art is the best exercise of all, when the brain is suffering
from overstrain. But taste will guide in this. The great matter is to
have pleasurable, easy, and natural employment for the brain. This and
not work is strengthening "exercise," whether in child or man. So far
as we can we should see that the weary get it. For he who procures this
for his fellow works immense good.

We have seen, for instance, a student attacked with dysentery while in
the hardest part of the session at the university. His whole system
became prostrate, and muscular activity to a very small degree would
have killed him; so would the continued mental toil necessary to go on
with his studies. Yet his brain was in need of exercise almost from the
first appearance of his disease. He must have this or be miserable, and
not