if the condition is recognized early in the disease, while if 

 treatment is delayed, there will be little hope. 



The only way in which these physical defects can be de- 

 tected early enough to check their course is through a com- 

 plete examination of the whole body by a competent physi- 

 cian. It is the conviction of public health authorities that 

 every person over forty-five should consult a physician at least 

 once a year, for a complete examination of the whole body, 

 to learn in time of the beginnings of disease and the precautions 

 necessary to prevent it from extending. Such a course would, 

 it is conservatively estimated, add five years to the average 

 life of persons between forty-five and fifty years of age. 



MAN AND THE MICROBE 



Good and Bad 

 Microbes 



There are many different kinds of microbes (or little living 

 things, which is the meaning of the word), 

 some of them classified by the biologist as 

 animals and some as plants. Most microbes 

 are harmless and some are actively beneficial to man, as, for 

 example, the bacteria which ripen cream and make vinegar 

 and those which fix the nitrogen of the air and make it avail- 

 able for the food of higher plants. A few of the microbes, 

 however, are parasites which live in the tissues or on the 

 surface of the human body as a mold grows in jelly. As the 

 mold forms chemical products which give the jelly a musty 

 taste, so the microbes form chemical substances called toxins, 

 which poison the body and produce the symptoms of disease. 

 Disease germs are normally propagated only by transfer 

 from one human being (or animal) to an- 

 other. They may survive for a time out- 

 side the body, but with rare exceptions they 

 do not multiply under such conditions, but 

 gradually and progressively perish. In an experiment by the 

 English bacteriologist Houston, of 470,000 typhoid germs 

 placed in ordinary tap water, only 480 were alive after one 



28 



Where Disease 

 Germs Come 

 From 



