THE STORY OF THE BACTERIA. 79 



vidual 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 individ- 

 ual or animal. 



The Bacillus tuberculosis can be cultivated 

 artificially in the laboratory on potatoes or 

 other solid media, provided the surfaces are 

 kept always moist and the temperature kept 

 approximately at that of the human body. It 

 does not grow in nature outside of the human 

 or animal body, but it may remain alive for a 

 long time, even in the thoroughly dry condi- 

 tion, and ready to grow again when it gets into 

 the body under favorable conditions. 



The conclusions which almost thrust them- 

 selves upon us from what we have thus learned 

 about tuberculosis are very plain. Tubercu- 

 lar cattle ought to be killed at once and 

 their carcases burned or otherwise rendered 

 innocuous just as soon as the disease is 

 discovered, and never allowed to get into the 

 markets. Pecuniary losses which individuals 

 might thus suffer are not worthy of a moment's 

 consideration as weighing against such obvi- 



