THE STORY OF THE BACTERIA. Ill 



we have seen above, there is a certain heredi- 

 tary predisposition to tuberculosis which is 

 resident in the body cells themselves and of 

 the exact nature of which we are quite igno- 

 rant, there is little doubt that one of the most 

 important reasons why tuberculosis is apt to 

 run in families is that children and relatives of 

 consumptives are more liable than others to 

 come in direct contact with the disease-pro- 

 ducing germs, which have been thrown off 

 from the bodies of their house-mates under 

 conditions which permit of their drying and 

 inhalation as dust. 



Theatres and churches, especially the 

 former, are apt, as is well known, to be alto- 

 gether inadequately ventilated. The headache 

 and malaise which are so prone to follow a 

 visit to many of our theatres, are evidences of 

 the bad air which we are usually forced to 

 breathe there ; but the more subtle dangers 

 here, as elsewhere, lurk in the dust which 

 equally with the bad air is forced upon us. 



No adequate means exist in most theatres 

 for ridding the air of the dust. The best of 

 them indeed are swept and " dusted " system- 



