The Bacteria of Consumption 93 



Finally, every individual has in his respira- 

 tory tubes an arrangement of tiny cells whose 

 free surfaces are covered with little hair-like 

 processes called cilia. These are ceaselessly 

 waving to and fro, and tend to sweep up and 

 away from the lungs foreign particles which 

 may be breathed in with the air. But not- 

 withstanding all these conditions which serve 

 to guard the exposed individual against the 

 disease-producing bacteria, it still remains true 

 that no man can acquire tuberculosis without 

 getting into his body this particular bacillus 

 from some infected individual or animal. 



Now as to tuberculous cattle as sources of 

 infection. Formerly the meat of such cat- 

 tle, which might be eaten uncooked, was a 

 noteworthy menace. But the State and 

 Federal control of diseases of cattle, whose 

 health by the way excites a much more vivid 

 interest in governmental circles than does 

 the health of man, is now so effective that 

 we need not consider it further here. But 

 the milk of tuberculous cows frequently con- 

 tains virulent tubercle bacilli and frequently 

 comes to the markets. 



