THE CONTROL OF HEALTH 379 



we now know that many diseases are definitely passed from 

 one person to another either (1) by contact, or (2) by taking 

 into the body ' 'particles" given off from the body of the sick 

 individual. Other diseases are caused by the body being 

 invaded by certain of the lower animals (e. g. malarial organism, 

 trichina), or by bacteria. 



"Contagious" and "infectious" diseases are now considered 

 essentially identical, being communicable. Among these 

 are typhoid fever, cholera, measles, mumps, whooping cough, 

 smallpox, communicable from man to man. From the 

 lower animals man "catches" tuberculosis, anthrax (splenic 

 fever) from cattle, malta fever from goats, malaria from 

 mosquitoes, plague from rats, and tapeworms from various 

 meats. 



The main problem in avoidance of disease concerns those 

 which, in bacterial form, are passed from man to man. These 

 organisms secure an entrance generally in one of three ways: 

 (1) in the food we eat; (2) in the air we breathe; (3) by way 

 of the skin, through natural pores or through injured surfaces. 



Two fundamental facts of bacteriology must be kept in 

 mind ; bacteria thrive either when in moist substances or when 

 dry or semi-dry so that they may float in the air, either free, 

 or attached to dust. Dust blows about and settles every- 

 where, e. g. on clothing, hands and face, on solid and liquid 

 foods if exposed, eating and cooking utensils, furniture of all 

 sorts, curtains and floor coverings. These are mentioned 

 that we may not forget what may be sources of bacterial 

 infection, and how thoroughly all the articles in a room with 

 a sick person may be the lodging places of disease bacteria. 

 Such articles as are nearest him are most liable to carry them, 

 e. g. personal clothing, bedding, handkerchiefs, knives, forks, 

 spoons, dishes, and all containers of waste material. 



After handling such articles as these just mentioned, if one 

 is to safely guard against infection, the hands should be 

 thoroughly disinfected by using germ-killing washes, such 



