"tobacco heart."

Tea and coffee contain a drug, called caffeine, which acts upon the
nervous system and which may, on this account, interfere with the proper
control of the heart. In some individuals the taking of a very small
amount of either tea or coffee is sufficient to cause irregularities in
the action of the heart. Tea is considered the milder of the two liquids
and the one less liable to injure.

*Effect of Rheumatism.*—The disease which affects the heart more
frequently than any other is rheumatism. This attacks the lining membrane,
or endocardium, and causes, not infrequently, a shrinkage of the heart
valves. The heart is thus rendered defective and, to perform its function
in the body, must work harder than if it were in a normal condition.
Rheumatic attacks of the heart do most harm when they occur in early
life—the period when the valves are the most easily affected. Any tendency
toward rheumatism in children has, therefore, a serious significance and
should receive the attention of the physician. Any one having a defective
heart should avoid all forms of exercise that demand great exertion.

*Strengthening of the Blood Vessels.*—Disturbances of the circulation,
causing too much blood to be sent to certain parts of the body and an
insufficient amount to others, when resulting from slight causes, are
usually due to weakness of the walls of the blood vessels, particularly of
the muscular coat. Such weakness is frequently indicated by extreme
sensitiveness to heat or cold and by a tendency to "catch cold." From a
health standpoint the preservation of the normal muscular "tone" of the
blood vessels is a problem of great importance. Though the muscles of the
blood vessels cannot be exercised in the same manner as the voluntary
muscles, they may be called actively into play through all the conditions