of action, use
bromid of potassium, or, better, extract of _Viburnum prunifolium_ (black
haw), 40 grains, at intervals of two or three hours until five or six doses
have been given.

CONTAGIOUS ABORTION.

Contagious abortion (also known as epizootic abortion, enzootic abortion,
and slinking of calves) is a disease affecting chiefly cattle and to a
lesser degree other domestic animals, and characterized by an inflammatory
condition of the female reproductive organs, which results in the expulsion
of the immature young.

_History._--This disease has been known in England and continental Europe
for many years, and descriptions of it are mentioned in the writings of
Mascal, Lafoose, Skellet, Lawrence, St. Cyr, Zuendel, and Youatt. In the
early part of the eighteenth century British veterinarians recognized its
contagiousness, but it remained for Franck (1876), Lehnert (1878), and
Braeuer (1880) to produce the disease in healthy, pregnant cows by the
introduction of exudate and material from aborting animals. Nocard (1888)
isolated from the exudate between the mucous membrane of the uterus and
fetal membranes a micrococcus and a short bacillus which were found
continually in contagious abortion, but he failed to reproduce the disease
by inoculations of pure cultures of these organisms into healthy, pregnant
animals. In 1897 Bang, assisted by Stribolt, published their findings
regarding infectious abortion of cattle, in which they incriminated Bang's
bacillus of abortion as the causative agent. With pure cultures of this
bacillus they were able to produce the disease artificially and to recover
the same organism from the experimental cases. Since that time many noted
investigators, both in this country and in Europe, have confirmed these
findings.

_Cause._--The _Bacterium abortus_ of Bang is now generally recognized as
the causative agent of the disease of cattle. Formerly it was thought that
abortion was due to injury, such as blows, horn thrusts, falls, etc., or
the eating of spoiled feed and certain plants, and while this may be true
in a limited number of cases, careful investigations have demonstrated
these claims to be largely unfounded. It is now generally recognized that
when abortion occurs in herds from time to time, it is safe to assume that
the disorder is of an infectious nature and should be so treated.

_Natural mode of infection._--This phase of the disease is of greatest
importance for a clear underst