THE RELATION OF THE TUBERCULOUS COW TO PUBLIC 
HEALTH. 
By E. C. Schroeder, 
Superintendent Experiment Station , Bureau of Animal Industry , Department 
of Agriculture. 
Under the conditions of our present civilization the dairy cow fills 
a unique place ; her living- body is the source of the most important of 
all human foods ; she has become an essential factor among our mod- 
ern institutions ; remove her and either a substitute must be found or 
many thousands of young children will die of starvation. The woman 
who can feed her infant at her own breast until it is old enough to 
thrive without milk is nearer the exception than the rule, so that 
either the cow or some other milk-producing animal must, as a sheer 
necessity, be available to serve the purposes of a human foster mother. 
After children have passed the period during which milk is a requi- 
site article of food, most of them continue its use as a beverage and 
add butter to their diet as a second product from the cow. Later on 
cream and cheese are added, and the use of milk to some extent as a 
beverage, and of cream, butter, and cheese as regular, current articles 
of food, is continued to the end of life. Hence, even if we are not 
greatly influenced by the idea that it is disgusting and barbarous to 
eat substances that are obtained from the living bodies of diseased 
cows, we must feel that it is important to make a careful inquiry re- 
garding the transmissibility to ourselves, through the use pf dairy 
products, of the commonest disease with which dairy cows are af- 
fected. The need for this inquiry is emphasized by the knowledge 
that the commonest and most important disease of cows is also the 
commonest and most important disease of mankind, and by the fact 
that though the disease in question, tuberculosis, is one of the few in- 
fectious diseases to which widely different species of animals are sus- 
ceptible, its commonest victims are persons and dairy cows. 
The indispensable cause of tuberculosis is the multiplication of 
tubercle bacilli in the animal body. Bacilli do not grow and multi- 
ply in animal bodies until they have been introduced into them from 
1414— Bull. 56—09 34 (529) 
