INFLUENCE OF CHOLERA ON THE LOWER ANIMALS. 707 
logy of epizootic diseases which appear to demand greater 
elucidation in reference to cholera or choleroid affections, is 
the pathology of the gastro-intestinal mucous membrane, 
along with its morbid secretions or discharges, with a view 
to the establishment of a differential diagnosis between 
cholera and allied diseases 
The chief classes of cases to which the attention of ob- 
servers should be directed are — 
I. Epizootic diseases occurring during periods of immunity from epidemic 
cholera in man, preceded, or not, by sudden and extensive disease in culti- 
vated plants, such as the potato, vine, and cereals, and which are either 
marked by choleraic symptoms, or by sudden deaths, without any symptoms. 
II. Epizootic or sporadic diseases coincident with epidemic cholera in 
man, and marked by similar symptoms, or by sudden deaths. 
III. Seizures in certain domestic animals — especially dogs and cats — 
after licking the evacuations, or inhaling the effluvia of the clothing or bodies, 
of living or dead human cholera patients, or which have been exposed to 
other known sources of infection. 
The latter class of cases is invested with peculiar interest, 
and they ought to be carefully sought for and observed. A 
few cases are on record of dogs, which have accidentally 
swallowed the cholera evacuations of their masters or mis- 
tresses, being seized with and dying of cholera ; and it has 
also been stated, that animals thus affected have communi- 
cated the disease to man, in whom it has proved fatal.* 
Here, then, we have instances of the double transmissibility 
of cholera, [viz., — to and from man and the lower animals. 
But, in a question of such importance, it is necessary that 
the facts be repeatedly confirmed before they can be received 
as established and undeniable. In the examination of such 
cases, it is of great importance to determine whether the ap- 
parent cause of the disease was the swallowing of the evacu- 
ations, or the inhalation of the poison, or both — whether, in 
other words, the intestinal or the cutaneous and pulmonary 
systems were the first recipients of the poison. It is almost 
unnecessary to point out the bearing which the decision of 
such a question has upon the theory recently advanced by 
Dr. Snow and others — viz., that the germs of the disease are 
received directly into the alimentary canal, and there pro- 
duce their poisonous effects. It is, moreover, advisable to note 
the precise period after discharge at which the evacuations 
were swallowed, since recent authors maintain that these are 
poisonous, and can communicate the disease, only at particu- 
* Some such instances will be found in a valuable paper of Mr. Marshall’s 
on the Communicability of Cholera to Animals. ‘ British and Foreign Med.- 
Chirurgical Review,’ April, 1853. 
