remaining available for its restoration to health; from the degree
of emaciation one can approximate the length of time the animal has been
ill. The age and breed of the animal, as well as its constitution and
temperament, are among the things that have to be taken into account in
making a diagnosis and in overcoming the disease.

_The mucous membrane._--The mucous membrane should in all cases be
examined. It can be readily seen by everting the eyelids or by an
inspection of the lining membrane of the nostrils.

Paleness of the mucous membrane indicates weak circulation or poor blood
and may result from disease, hemorrhage, or from inappropriate feed.

In healthy animals increased redness of the mucous membrane occurs from
pain, excitement, or severe exertion, and in such instances is always
transitory. In certain pathological conditions, such as fevers and
inflammation, this condition of the mucous membrane will also be found. The
increased redness of the mucous membrane lasts during the duration of the
fever or inflammation.

A bluish or blue mucous membrane indicates that the blood is imperfectly
oxidized and contains an excess of carbon dioxid, and is seen in serious
diseases of the respiratory tract, such as pneumonia, and in heart failure.

_The secretions._--The secretions may be diminished, increased, or
perverted. In the early stage of an inflammation of a secretory organ its
secretion is diminished. In the early stage of pleurisy the serous membrane
is dry, and as the disease advances the membrane becomes unnaturally moist.
The products of secretion are sometimes greatly changed in character from
the secretion in health, becoming excessively irritant and yielding
evidence of chemical and other alterations in the character of the
secretion.

_Cough._--Cough depends upon a reflex nervous action and may be primary
when the irritation exists in the lungs or air passages, or secondary when
caused by irritation of the stomach, intestines, or other parts having
nervous communications with the respiratory apparatus. A cough is said to
be dry, moist, harsh, hollow, difficult, paroxysmal, suppressed,
sympathetic, etc., according to its character. It is a very important
symptom, often being diagnostic in diseases of the respiratory organs, but
this is a subject, however, which can be more satisfactorily treated in
connection with the special diseases of the organs in question.

_Respiration._--In making an examina