Dust and Bacteria. 1 27 



ing out a sliver with a pin. If such germs happen to be 

 on the point of the pin, the mischief is easily done. Great 

 care should be taken in any such operation to use a 

 thoroughly clean needle or lancet. Formerly any surgical 

 operation that required opening the body cavity, either 

 the chest or the abdomen, usually resulted in death. Now- 

 adays such operations are commonly successful, because 

 surgeons sterilize their instruments, hands, and 'everything 

 used about the work. They kill any germs that might 

 be introduced. In a word, they Jiave learned to be 

 clean. 



In caring for a patient ill of any germ disease, one should 

 wash the hands in some disinfectant, such as chlorid of 

 lime, and should not touch the fingers to the lips; .igno- 

 rance of these simple rules has caused many deaths. 



Malaria. This is due to an animal germ (not a bac- 

 terium) that gets into the blood. It is introduced by mos- 

 quitoes that have bitten persons whose blood contains these 

 germs. 



The Bacteria of Putrefaction. Besides the disease- 

 producing bacteria, there are others that cause decay and 

 putrefaction of various kinds. They cause our richer foods 

 to " spoil," milk to turn sour, butter to become rancid, etc. 



While these bacteria do not cause disease in the human 

 body, they often make food poisonous. The cases fre- 

 quently reported of poisoning from eating ice cream, 

 cheese, sausage, etc., are in many cases due to bacteria 

 in them. We should, in the first place, be careful to get 

 good, fresh material. In the second place, it should be so 

 kept as to prevent the introduction and development of 

 bacteria in it. Bacteria need heat and moisture for their 

 growth just as higher plants do. 



