428 SANITATION 



stances that the germs produce. These substances are 

 violent poisons, called toxins; they injure the cells of the 

 body much as strychnine or other poisons would. Pto- 

 maines (to'-ma-ins), which cause so-called ptomaine 

 poisoning, are toxins produced in the decay of foodstuffs. 

 The disease germs that we take into the body when we are 

 "exposed" to a disease are not numerous enough to pro- 

 duce much toxin, so there is usually a period of time, 

 called the incubation period (incubation also means 

 "hatching"), during which the germs are multiplying, 

 and are producing enough of the toxins to give us the 

 symptoms of the disease. 



423. How Germs May Be Destroyed. While the 

 disease germs that get into the body do not always cause 

 disease, because of the power of the white corpuscles and 

 the germicides to destroy them, we are not safe if we 

 depend on this power alone. We must do all we can to 

 destroy the germs before they enter the body. Hence 

 we cleanse the body and its clothing, and our dishes and 

 floors. Since food for man is often food for germs, we 

 cook or bake most of our food. The high temperature of 

 boiling water and of the oven destroys the germs. 



To some of us the wiping up of dust ("dusting the 

 house") may seem an unnecessary performance. But if 

 a house is to be safe, the dust that collects must be re- 

 moved carefully; it may contain deadly germs. If a 

 house contains a great deal of heavy furniture and much 

 bric-a-brac, the labor of house cleaning is so great that 

 it may not be carried out often enough. The average 

 family needs to reduce greatly the quantity of its house 



