CONTAGIOUS DISEASES 



385 



vented, but on the other hand as one looks forward to the 

 future, it is encouraging to think that this mortality may be 

 very largely reduced through the spread of the knowledge 

 of how consumption may be cured and prevented. It is 

 the purpose of the next few pages to give some of the in- 

 formation which one needs in order to enable him to act his 



The closed window. 



Overwork. 



Crowded rooms. Mouth breathing. 



FIG. 151. Allies of consumption. 



part as an intelligent citizen in the widespread movement 

 to stamp out this disease. 



How bacteria leave and enter the body. Tuberculosis of 

 the lungs is caused by bacteria which live in the lungs, and 

 cause little rounded bodies known as tubercles. The bac- 

 teria are passing constantly into the saliva of the patient 

 and leave the body in the sputum. While the chief way 

 in which they are thrown out is in the act of expectora- 

 tion, they may also be thrown off in the mouth spray in the 



2C 



