634 MAN AS A CONQUEROR 



produced ])y the bacteria which causes scarlet fever when injected 

 into the arm indicates susceptibiUty by a sHght swoUing and redness 

 of the area. If the scarlet fever toxin is inoculated, the body will 

 work up an immunity against the disease. Another treatment con- 

 sists in using an antitoxic serum which combats the toxins of scarlet 

 fever in the same way as the diphtheria antitoxin combats the similar 

 diphtheria toxm. Still another child's disease which is now fought 

 by means of passive immunity is measles, where a serum obtained 

 from convalescent measles patients is used as an antitoxic measure. 



Other antitoxins are used against tetanus, a much dreaded infec- 

 tion. During the World War soil-infected wounds were immediately 

 treated with this antitoxin and with another worked up against 

 gas gangrene. In consequence the mortality from these infections 

 was much reduced. Antitoxins are also used against certain snake 

 venoms, the mechanism of immunity being apparently the same in 

 poisoning from snake venom as in toxic poisoning from bacteria or 

 other organisms. 



Are Parasitic Diseases Conquerable? 



In answer to this question, one has only to look at statistics 

 showing the lengthening life span. Certain diseases are nearly 

 conquered. Smallpox, diphtheria, typhoid, yellow fever, and rabies 

 are all almost in sight of the time when they will be under absolute 

 control. Some diseases are more difficult of conquest but are rapidly 

 coming under control, for example, children's diseases such as measles, 

 whooping cough, and scarlet fever, all of which are being attacked 

 through immune sera or vaccines. The difficulty here is that because 

 of the length of the incubation period, children often infect others 

 when their parents do not actually know that they have a given 

 disease. Malaria, tuberculosis, and hookworm are also rapidly 

 coming under control, due to the application of recent discoveries. 

 Certain of our parasitic enemies still remain unconquered. Pneu- 

 monia and influenza are among the greatest causes of death when 

 they go on epidemic rampages. The common cold still remains an 

 unconquered enemy both because of its insidiousness and because 

 people do not consider it serious enough to treat as a real disease. 

 Infantile paralysis, meningitis, and many tropical diseases are also as 

 yet uncontrolled. The two venereal diseases, gonorrhea and syphilis, 

 are much more serious enemies than is realized, not only because 

 they are difficult to control but also because of the intimate nature 



