HOUSEHOLD BACTERIOLOGY 



Point of 



Attack 



Method of 



Infection 



Outside of the body disease producing bacteria may 

 remain alive under very varying circumstances, but as 

 a rule they do not multiply as most of them require a 

 temperature equal to that of the body. There are ex- 

 ceptions, as, for example, the growth of the bacteria 

 of typhoid fever in milk, and many others which 

 reproduce in the laboratory under artificial conditions. 

 The lower animals may serve as a breeding ground 

 for some of the disease germs dangerous to man. 



For most of these germ diseases there is some spe- 

 cial portion of the body which is more susceptible than 

 any other. We associate pneumonia and usually tu- 

 berculosis with the lungs, diphtheria with the throat, 

 typhoid fever with certain parts of the intestines. From 

 these most usual points of attack may be inferred the 

 most common methods of infection. 



When the seat of the disease is some portion of the 

 respiratory system nostrils, throat or lungs it is 

 probable that dust entering with the inhaled air car- 

 ried the germ, or it came by contact with the lips, as 

 in kissing ; when it is in the digestive tract, that food 

 or drink was the vehicle ; or when in the skin or outer 

 tissues, that there was actual contact with the germ 

 either as dust, dirt, or germ bearing material from a 

 previous case of the disease, which gained entrance 

 through some puncture or a break in the skin. 



When we remember that all such diseased condi- 

 tions due to germs are infectious, we shall exercise 

 great care in preventing contact with the diseased 



