The Protection of Health 589 



Non-infectious diseases. The non-infectious diseases are 

 not caused by microorganisms. They may be due to faults 



FIG. 173. Types of pathogenic bacteria : a, tuberculosis ; b, diphtheria ; 

 c, typhoid fever ; d, vibrio of cholera ; e, anthrax ; /, erysipelas ; g, pneumonia. 



in diet, in work, or in rest. They include such diseases as 

 diabetes, some forms of indigestion, nervous disorders, and 

 certain kinds of heart trouble. 



290. Transfer of disease germs. The infective organism, 

 or that which causes a disease, must be transferred by some 

 agent from a patient or a disease carrier to another person who, 

 if susceptible, becomes a victim of the disease. The agencies 

 and ways by which pathogenic germs are transferred are now 

 definitely known in the case of several common diseases. The 

 spread of infectious disease can be controlled by blocking the 

 ways or by destroying the agencies of transmission. The 

 essential facts may be presented in the following way : 



I. Infective germs of many diseases are thrown off by way 

 of the mucus-lined openings of the body, such as the nose and 

 mouth . They gain entrance into the body of a healthy individual 

 through such openings. The germs which cause tuberculosis, 

 pneumonia, typhoid fever, diphtheria, influenza or grippe, 

 whooping cough, colds, measles ; scarlet fever, cholera, and diar- 

 rheal disorders are usually received through the nose or mouth. 

 The germs causing smallpox, chicken pox, and leprosy escape 

 through sores and attack another individual through cuts, 

 sores, or the mucus-lined openings, as the nose and mouth. 



