OUR BODIES AND HOW WE LIVE 



poisoned air due to cesspools, drains, and sewers is a fre- 

 quent source of disease. Sewer gas, the foul air from 

 chemical works, bone and soap factories, and many other 

 manufacturing places, may be hurtful to health. 



Certain occupations may shorten life by exposure to air 

 laden with impurities. Thus, there is the " miner's con- 

 sumption," or "black lung," due to the dust which is 

 breathed into the lungs, and acts like so many little splin- 

 ters in the delicate air cells. Refiners of mercury work 

 in a deadly atmosphere. Those who work on steel, emery, 

 cutlery, pottery, etc., also suffer from the irritating dust 

 floating in the air. 



Other impurities are highly injurious to the lungs, as the 

 dust in match factories, white-lead works, and copper and 

 brass foundries. In fact, among some classes of factory 

 workers the rate of mortality is higher than among firemen, 

 freight brakemen, and men in other pursuits known to 

 involve great risk of life. 



236. How Bacteria may be carried in the Air. Many 

 kinds of bacteria are carried in the air. Some of these 

 germs may grow and produce disease if taken into the body 

 through the air passages, in the food, or in drinking water. 

 Thus, we shall learn that the germs of certain infectious 

 diseases may be carried in the air and produce similar diseases 

 in persons who may become infected by them. 



The germs of disease after floating about in the air for a 

 time may settle with the dust. If an infected room is not 

 properly swept and dusted, there is an ever-present danger 

 of spreading contagious diseases. Hence a sick room should 

 be kept rigidly clean and furnished with a constant supply 

 of pure, fresh air. It is well knowa that the dust in the 

 streets of large towns contains the germs of disease. 



