556 APPLIED BIOLOGY 



towels) ; (2) from dust arising from the dried sputum of a 

 tuberculous victim ; (3) possibly from milk of tuberculous 

 cows; (4) by flies which carry the bacteria from sputum. 

 The first line of danger is easily avoided. Especially should 

 those suffering from tuberculosis or whose friends are 

 afflicted get from the Society for the Prevention of Tuber- 

 culosis, in New York City, the free circulars which give rules 

 for preventing the spread of the disease, and follow them 

 carefully. Doubtful milk should always be pasteurized, or 

 boiled. The danger from dust is impossible of avoidance by 

 individuals so long as the spitting nuisance continues. For- 

 tunately, drying and sunlight kill most of the germs out of 

 doors, and good ventilation and cleaning reduce the danger 

 indoors. 



So far as personal hygiene is concerned, the most important 

 preventive measure against pulmonary tuberculosis is keep- 

 ing in general good health by good food, outdoor exercise, 

 fresh air, good sleep, and avoiding colds. So long as the 

 body is in good condition there is little danger of the bacteria 

 getting a chance to flourish in the lungs; and even if the 

 disease has begun to develop, a cure may be effected by 

 careful attention to the rules of hygiene which physicians 

 and special books and pamphlets prescribe. 



Many children's diseases (whooping cough, measles, 

 mumps, chicken-pox, etc.) are believed to be contracted 

 through the respiratory organs. The best protection is (1) 

 keeping away from cases of such diseases, and (2) avoiding the 

 use of pencils, toys, towels, handkerchiefs, drinking cups, 

 etc., which may have been in contact with the mouths of 

 other children, who may carry the germs although apparently 

 well. These and the biological rules given in 488 will pre- 

 vent most epidemics of children's diseases. 



486. Infection by Insects. The relations of mosquitoes 

 and flies to disease have been stated in 329, 330. Constant 

 warfare should be waged against these insects. 



