DUST AND ITS DANGERS. 8/ 



diminished by the fact that in drying, and 

 especially in sunlight, a large number of the 

 tubercle bacilli die and so become harmless. 



There is one way, however, in which the 

 tubercle bacillus is frequently transmitted from 

 one person to another in full vigor and viru- 

 lence, which is of such great importance that 

 we must consider it here, though it does not 

 strictly belong in a discourse upon dust. 



In sneezing and coughing, particles of saliva 

 or bronchial or nasal secretion, or material from 

 the lungs of those who are the victims of pul- 

 monary tuberculosis and may contain bacilli, 

 are thrown out in the form of a fine spray. 

 This is particularly the case in sneezing. This 

 fine spray may float in the air for a consider- 

 able time and can be breathed in by persons 

 several feet from a vigorous sneezer. 



There is abundant evidence that in this way 

 intimate association with tuberculous persons 

 may lead to infection. The prevention of this 

 evil lies in holding the handkerchief over the 

 nose and mouth in coughing and sneezing. 

 This counsel of decency is worthy of conside- 

 ration at all times where persons are closely 



