CHAPTER XLVI 



CERTAIN OTHER 

 BACTERIA 



Fleas may carry bubonic 

 plague. 



The louse may carry typhus 

 fever. 



How may colds be prevented? Have colds any serious effects on the 

 body? Is there any relation of asthma to food? Is it possible or 

 desirable for children to avoid the so-called children's diseases? 



Causes of colds. It is generally conceded that there are two 

 types of inflammation called colds. The first type is caused by 

 bacteria and is a real infection. The germs may attack a certain 

 local area, thus causing a cold in the head, a sore throat, laryngi- 

 tis, or tonsillitis, or they may have general widespread effects as 

 in grippe. The second type of cold is caused by physical agents 

 such as irritant gases or dust. Colds and even pneumonia have 

 been caused by breathing in talcum powder. Dust inhaled in 

 working at trades such as diamond polishing, metal polishing, or 

 marble quarrying may cause colds, followed by pneumonia, or 

 tuberculosis. It is the physical material which starts the irrita- 

 tion, then bacteria enter the irritated tissues and set up infections. 

 Other factors that may cause colds are dry heated air, drafts, 

 sudden changes of temperature, exposure to cold and wet, im- 

 proper food, and constipation. 



Effect of colds on the body. Bacteria causing colds are usually 

 present in the mucous membrane of the nose, mouth, and throat. 

 When the resistance of the body is lowered, it is thought that 



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