402 
W. H. HARBAUGH. 
products of mankind is derived from from the bovine race. 
Koch’s discovery having established beyond all question the 
contagious and infectious nature of tuberculosis, it opened a 
broad field for scientific investigations, and the starting-point of 
all these investigations was the complete confirmation of the 
fact that the bacillus of Koch being the causal agent of the 
disease, tuberculosis could not start or exist in the absence of 
its specific germ, and the point was forever settled, that m order 
for man or any other animal to have consumption, or any other 
form of tuberculosis, the bacillus of Koch must gain entrance 
into the system, and there find proper lodgment m order that it 
may commit its usual havoc. After these facts were ascertained, 
the questions of paramount importance were to ascertain the 
general modes of infection, or tranmission from one to another, 
and the safest and best means of avoiding the dangers of 
infection. 
Hundreds of investigators entered the field of experimenta¬ 
tion, and the results of their work have startled and agitated the 
civilized world. For obvious reasons, the experiments have 
been confined to the lower animals, but the disease being the 
same and due to the same cause, the facts ascertained apply in 
all respects to similar conditions in man and the lower animals. 
It has been positively shown by thousands of experiments 
that the disease is transmissible from one animal to another of 
the same species, and from one species to another. It has been 
proven that no matter how the germs may enter the system, 
whether inhaled, taken in with food, or inoculated,the disease is 
liable to ensue ; tuberculosis in various forms has been produced 
in a large percentage of such experiments. A tuberculous animal 
placed among animals communicates the disease with certainty 
to animals previously healthy. Milk from an affected cow fed 
to cats, calves, hogs, guinea pigs, etc., produces the disease m 
them. Milk from an affected cow inoculated into other animals 
produces the disease. Sputa coughed up by man and carelessly 
spit out, has been licked up and devoured by cats and dogs an 
produced the disease in them. 
