cause there is a possibility of the pus getting into the circulation.

In the operation of bleeding the instruments should be clean and free from
rust. If the skin is not sufficiently opened, or when closing the wound the
skin is drawn out too much, blood may accumulate in the tissue, and if it
does it should be removed by pressing absorbent cotton or a sponge on the
part. Care should also be used in opening the vein, so that the instrument
may not pass entirely through both sides of the vein and open the artery
beneath it.

* * * * *

DISEASES OF THE HEART, BLOOD VESSELS, AND LYMPHATICS.

DESCRIPTION OF PLATE.

PLATE VII:

Diagram illustrating the circulation of the blood. The arrows indicate the
direction in which the blood flows. The valves of the heart, situated
between the right auricle and ventricle, and left auricle and ventricle,
and between the ventricles and large arteries, are represented by curved
lines. These valves are intended to prevent the flow of blood in a
direction contrary to that indicated by the arrows.

[Illustration: PLATE VII. DIAGRAM OF THE CIRCULATION OF THE BLOOD.]

* * * * *

NONCONTAGIOUS DISEASES OF THE ORGANS
OF RESPIRATION.

By WILLIAM HERBERT LOWE, D. V. S.

DIAGNOSIS.

In the determination of disease in the human being the physician, in making
his diagnosis, is aided by both subjective and objective symptoms, but the
veterinary physician, in a very large majority of cases, is obliged to rely
almost solely upon objective symptoms, and perhaps in no class of diseases
is this more true than in the exploration of those under consideration.
This condition of affairs has a strong tendency to develop observation and
discernment in the veterinarian, and not infrequently do we find that the
successful veterinary practitioner is a very accurate diagnostician. In
order to make a differential diagnosis, however, it is not only necessary
to know the structure and functions of the organs in health, but to adopt a
rigid system of details of examination, without which successful results
can not be reached.

_History._--The history of a case should always be ascertained so far as
possible. The information obtained is sometimes unsatisfactory and not to
be depended upon, but even when this is the case it is advisable to weigh
the evidence from every point of view.

In connection with the history of every case it is alw