such as tuberculin and malein, enable the owner to rid his herds of
tubercular cows and glandered horses before these diseases have become far
enough advanced to be recognized by the visible symptoms alone. Black leg,
anthrax and hog-cholera vaccines are valuable agents in the control of
disease. In the treatment of fistula and infectious abortion, bacterins may
be used. There are many other germ diseases and infections for which
vaccines and bacterins may be used. However, we must not depend wholly on
these agents in the control of disease. We must possess a knowledge of the
manner in which the infection is spread, for without this knowledge we
would be unable to prevent its dissemination over a wide area.

Medicinal Treatment.--The average stockman or veterinarian is more familiar
with the treatment of disease with drugs than he is with the preventive
measures just described. This statement does not imply that a knowledge of
medicinal therapeutics is not of the greatest importance in the treatment
of disease. The ultimate object of all drugs is both to prevent and cure
disease, but the injudicious use of a drug does neither. A discussion of
this subject cannot be entered into here, and because of its largeness it
is not advisable to discuss it further than a brief summary of the methods
of administering drugs.

Administration of Drugs.--Drugs may be administered by the following
channels: by way of the mouth, in the feed or as a drench; by injecting
into the tissues beneath the skin or hypodermically; by rubbing into the
skin; by the air passages and the lungs; and by injecting into the rectum.

If the animal is not too sick to eat and the drug does not possess an
unpleasant taste, it may be given with the feed. If soluble, it may be
given with the drinking water, or in any case, it may be mixed with ground
feed if this method is to be preferred. In all cases the medicine must be