influence of contagion.

From the results of these experiments, the commission drew the following
conclusions:--

_1stly._ The epizooetic pleuro-pneumonia is susceptible of being
transmitted from diseased to healthy animals by cohabitation.

_2dly._ All the animals exposed do not take the disease; some suffer
slightly, and others not at all.

_3dly._ Of the affected animals, some recover and others die.

_4thly._ The animals, whether slightly or severely affected, possess an
immunity against subsequent attacks.

These are the general conclusions which the commission deemed themselves
authorized to draw from their experiments. The absolute proportion of
animals which become affected, or which escape the disease, or of those
which die and which recover, as a general rule, cannot be deduced from
the foregoing experiments, which, for such a purpose, are too limited.
The commission simply state the numbers resulting from their
experiments. From these it transpires that forty five of the animals
became severely affected with pleuro-pneumonia, and twenty-one per cent.
took the disease slightly, making the whole sixty-six per cent. which
were more or less severely attacked. Thirty-four per cent. remained free
from any malady. The proportion of animals which re-acquired their
wonted appearance of health amounted to eighty-three per cent., whereas
seventeen per cent. died. Many minor points might be insisted on, but it
is sufficient here to say, that the most careful analysis of all facts
has proved to practical veterinarians, as well as to experienced
agriculturists, and must prove to all who will calmly and
dispassionately consider the point, that pleuro-pneumonia is
pre-eminently an infectious, or contagious disease.

[Illustration: THE TWINS.]

_Symptoms._--From the time that an animal is exposed to the contagion to
the first manifestation of symptoms, a certain period elapses. This is
the period of incubation. It varies from a fortnight to forty days, or
even several months. The first signs, proving that the animal has been
seized, can scarcely be detected by any but a professional man; though,
if a proprietor of cattle were extremely careful, and had pains-taking
individuals about his stock, he would invariably notice a slight shiver
as ushering in the disorder, which for several days, even after the
shivering fit, would limit itself to slight interference in breathing,
readily detected on auscultation. Perhaps a c