596 
E. P. NILES. 
When the infection is through the respiratory organs the subject 
must be brought in close contact or housed with others suffering 
from the disease. Not so with those that are infected through 
the digestive tract. For the germ may be carried for miles by 
other smaller animals. Since rats may be infected they may 
become carriers of the bacillus; feeding in the feed troughs and 
mangers as they do, one tuberculous rat may easily infect a 
whole herd of cattle by contaminating the food of these animals. 
Cats which have slept in the mangers of tuberculous animals 
have been known to contract the disease. They, too, may be 
■» 
common carriers of the bacillus, distributing them alike among 
the human family and the lower animals. It is also reasonable 
to suppose that the cat may contract the disease from the hu¬ 
man subject, and from them communicate it to the lower animals. 
It was formerly supposed that dogs showed perfect immunity 
against the disease, but recent experiments have demonstrated 
that they are by no means uncommon subjects. They, there¬ 
fore, may distribute the disease far and wide. The earth worm 
is also said to distribute the disease by bringing to the surface 
the germs from tuberculous animals which have been buried. 
Buzzards, though possibly not susceptible to the disease, may 
also distribute the germ in every direction from the carcasses of 
tuberculous animals which have been allowed to lie on the sur¬ 
face of the soil. Diseased cattle may infect the pastures, barn 
yards, springs, etc. These are all possible sources of contamin¬ 
ating the food and water consumed by the healthy individual, 
thereby indirectly affecting animals which, in some instances, 
may be miles away from the primary cause of infection. 
Infection through the skin is rare, and usually takes place 
through an abraded surface. 
Infection through the generative organs is also comparative¬ 
ly rare, and is the result of allowing healthy animals to be bred 
to those suffering from genital tuberculosis. 
Infection of the unborn foetus through the dam may occur, 
but in such instances abortion is the rule ; the foetus rarely 
ever being born alive with tuberculosis. An abortion in a hu- 
