STATE HYGIENE 575 



crowding and exposing a large number of susceptible 

 animals to infection, and by the absence of sunlight, the 

 presence of which is fatal to the bacilli. 



Dark, ill-ventilated, and overcrowded cattle sheds cannot 

 of themselves produce tuberculosis, but once a tuberculous 

 subject is introduced into such, all the conditions for infec- 

 tion exist in the most complete form. 



If stock owners would but take this lesson to heart, the 

 first step in the eradication of this plague would be made ; 

 if affected animals are allowed to remain among the healthy 

 there can be but one result ; if a case of the disease is in- 

 troduced among healthy stock the results can be easily fore- 

 told. Herein lies the entire question of the eradication of 

 this disease from our herds ; expense and indifference alone 

 stand in the way. 



The three epizootic cattle diseases previously described are 

 very highly infectious, but not so tuberculosis ; prolonged 

 contact appears essential for infection, the disease moves 

 slowly, so much so, in fact, that an animal may be a focus 

 of infection, and yet present every sign of health. 



In this respect one's sympathies are with the stock owner, 

 who naturally fails to realize that what appears to be healthy 

 stock can in any way be dangerous, and it is not surprising 

 if he finds a difficulty in believing the tale that tuberculin 

 is capable of unfolding. 



Turning now to an extremely vexed question, which is 

 still far from settled, we must consider how far bovine 

 tubercle is capable of being conveyed to man, and what risk 

 is incurred by humans in the consumption of milk and 

 flesh of tuberculous animals. We may at once say that the 

 communication of the disease from animal to animal by 

 infected flesh or milk is a point long ago settled by experi- 

 mental inquiry and admits of no doubt whatever. 



The real point at issue is whether man can be infected in 

 this way ; this opens up the immense question of milk and 

 meat supply, and whether it is possible for man to be affected 

 by using the flesh and milk of tubercular animals. 



Had the question been asked a little over three years ago 



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