DUST AND ITS DANGERS. 59 



furnish the unknown conditions, and in them 

 the bacillus grows more or less rapidly ; such 

 persons or animals are said to be predisposed 

 to the disease consumption. 



A great deal of misery and wearing appre- 

 hension have been caused in the years which are 

 past by the widespread notion that consump- 

 tion < may be inherited. Modern researches 

 show that this notion is not well-founded. It 

 is true that there is a subtle make-up of the 

 body cells in certain persons, some entirely 

 mysterious nutritive condition, which renders 

 their bodies especially favorable for the growth 

 of the tubercle bacillus, and that this indefinite 

 and ill-understood peculiarity may be inherited. 

 But that is all. If the tubercle bacillus can 

 be kept away from them, even predisposed 

 persons cannot get consumption, for this dis- 

 ease without the bacillus cannot exist, and the 

 bacillus does not as far as we know pass from 

 the mother to the unborn child. But this so- 

 called predisposition is not always inherited; 

 it may be and often is acquired, sometimes in 

 ways which we know about, sometimes in ways 

 which we do not fully understand. 



