4 i8 



APPLIED PHYSIOLOGY 



The saliva and the mucus from the nose contain the germs in most 

 infectious diseases. In ordinary breathing we do not expel the germs 

 from the nose and mouth, but in talking and sneezing and coughing we 

 often expel tiny drops of liquid which may be full of disease germs. 

 These drops may dry in a moment, and then the germs may float in the 

 air as dust. The result is the same as if we had breathed the germs 

 directly into the air. Thus foul and dusty air usually contains disease 

 germs. Most infectious diseases are now spread by means of the dis- 

 charges from the nose and throat, for these two organs are in use during 

 every moment of our lives, while we can easily control the other means 

 by which germs leave the body. 



724. Means of spreading disease germs. Disease germs 

 are likely to be found on anything that has been soiled by 

 the discharges from the body. Dust and dirt containing 



A safe form of public drinking 

 fountain. 



An unsafe drinking place in a 

 public school. 



the germs settle on our floors and carpets. Everything on 

 which saliva falls may contain the germs. The habit of 

 spitting spreads millions of germs. Soiled dishes, handker- 

 chiefs, towels, bedclothing, and underwear are all likely to 



