a
are examples of purely vegetable products; iron, mercury, and arsenic
are equally well known as distinctly mineral products, while cod-liver
oil is the most familiar illustration of an animal remedy. Ordinarily
a combination of products best serves the ends of the physician.

Substances which, like cod-liver oil, serve as food to a worn-out
body, or, like iron, tend to enrich the blood, or, like quinine, aid
in bringing an abnormal system to a healthy condition, are valuable
servants and cannot be entirely dispensed with so long as man is
subject to disease.

But substances which, like opium, laudanum, and alcohol, are not
required by the body as food, or as a systematic, intelligent aid to
recovery, but are taken solely for the stimulus aroused or for the
insensibility induced, are harmful to man, and cannot be indulged in
by him without ultimate mental, moral, and physical loss. Substances
of the latter class are known as narcotics and stimulants.

237. The Cost of Health. In the physical as in the financial world,
nothing is to be had without a price. Vigor, endurance, and mental
alertness are bought by hygienic living; that is, by proper food,
fresh air, exercise, cleanliness, and reasonable hours. Some people
wish vigor, endurance, etc., but are unwilling to live the life which
will develop these qualities. Plenty of sleep, exercise, and simple
food all tend to lay the foundations of health. Many, however, are not
willing to take the care necessary for healthful living, because it
would force them to sacrifice some of the hours of pleasure. Sooner or
later, these pleasure-seekers begin to feel tired and worn, and some
of them turn to drugs and narcotics for artificial strength. At first
the drugs seem to restore the lost energy, and without harm; however,
the cost soon proves to be one of the highest Nature ever demands.

238. The Uncounted Cost. The first and most obvious effect of opium,
for example, is to deaden pain and to arouse pleasure; but while the
drug is producing these soothing sensations, it interferes with bodily
functions. Secretion, digestion, absorption of food, and the removal
of waste matters are hindered. Continued use of the drug leads to
headache, exhaustion, nervous depression, and heart weakness. There is
thus a heavy toll reckoned against the user, and the creditor is
relentless in demanding payment.

Moreover, the respite allowed by a narcotic is exceedingly brief, and
a depression