234 
EXTRACTS FR<»M FOREIGN PERIODICALS 
the more constantly animals are housed, and the smaller and 
worse ventilated the buildings are in which they are confined 
the greater will be the risk of the disease spreading, provided 
there is one tuberculous individual in the stock. A cow that 
is the subject of tuberculosis of the lungs expels tuberck 
bacilli from the air passages in the act of coughing. Thesi 
bacilli, when desiccated, rise as particles of dust, they an 
then apt to be inhaled by other inmates of the same building 
Such in the great majority of cases is the mode of infectioi 
in the case of cattle, and hence the two main things to be at 
tended to with a view to prevention are—(i) To permit m 
animal suspected of being tuberculous to stand in the sam< 
building with other animals ; and (2) to see that the building 
in which cattle, and especially dairy cows, are housed, an 
roomy and well ventilated. To provide sufficient aii-spao 
and adequate means of ventilation in the most obvious manne 
diminishes the risk of one animal infecting another. No wile 
animal in a state of nature has ever been known to die Iron 
tuberculosis ; and, with the exception of the few cases ii 
which the disease is inherited, or transmitted to the calf b; 
means of the milk, cattle of even the most susceptible breed 
remain free from tuberculosis as long as they are not housed 
In short, tuberculosis is a disease of domestication of clos* 
housing and bad ventilation. 
Long before the discovery of the tubercle bacillus, an< 
even before it was generally recognized that tuberculosis i 
contagious, medical men had come to the conclusion that ii 
sufficient ventilation had much to do with the prevalence c 
the disease among human beings, and a most convincing proc 
of the correctness of their view was furnished by the sudde 
decline in the mortality from phthisis among our soldier 
when a greater air-space per man and better means of vent 
lation were provided in the barracks. Theie is eveiy reaso 
to believe that, in like manner, a great check would be put t 
the spread of the disease among cattle if byres were mad; 
larger and better ventilated. 
Sanitarians are agreed that in ordinary human habitation 
a cubic capacity of 600 to 800 feet should be provided ft. 
