334 



interfering with their nutrition. Sulfa 

 drugs should not be used except under 

 the direction of a physician. 



The sulfa drugs have a great variety of 

 uses: in pneumonia, instead of the sera 

 which are prepared with great difficulty 

 and expense; in surgery, against infec- 

 tion; against the streptococcus causing 

 sore throats; and recently even against a 

 virus in a widespread eye infection 

 (trachoma). 



More recently sulfa drugs combined 

 with iodine have been used successfully 

 to prevent infection by the sporeformers, 

 tetanus and anthrax germs. Sulfa drugs 

 alone have no effect on these. 



Penicillin. Fenicill'm (pen-i-silPin) is 

 another drug that is used against wound 

 infections. It is extracted from a mold. 

 Recently it has been made in small 

 amounts by chemists in the laboratory. 

 You have no doubt seen a blue-green 

 mold growing on cheese or other foods. 

 Several relatives of this blue-green mold 

 produce the substance which is extracted 

 and used as the drug, penicillin. Other 

 molds, too, have been found to yield 

 substances that stop the growth of bac- 

 teria. As time goes on, you may hear 

 more of streptomycin, and other com- 

 pounds that can be used to interfere with 

 the growth of germs in the human body. 

 Streptomycin is produced by bacteria 



Constant Care Is Needed for Health unit vi 



that live in the soil. Drugs such as these, 

 obtained from living organisms, are 

 called antibiotics (anti-by-ot'ticks). 



The conquest of disease. The story of 

 man's attempts to conquer disease is a 

 long and excitinij one. When Koch and 

 Pasteur proved that some diseases \\ ere 

 caused by bacteria, they opened up a 

 new approach to the problem of prevent- 

 ing and curing disease. Pasteur and others 

 showed that it was possible to prevent 

 disease by inoculation with weakened 

 germs. Later the use of antitoxins for the 

 cure of diphtheria and tetanus was dis- 

 covered. Other immune sera were used. 

 Still more recently tests for susceptibil- 

 ity were found. 



Then discoveries took a new turn. Be- 

 ginning with Ehrlich's discovery of a 

 chemical that could cure syphilis, a 

 whole series of chemical compounds has 

 come into use. Some, the sulfa drugs, 

 were produced by the chemist; others, 

 penicillin and streptomycin, have been 

 extracted from living organisms. They 

 have opened up new possibilities in the 

 prevention and cure of disease. To help 

 you sum up part of this problem do 

 Exercise 9. 



When these improved methods of 

 combating disease are made available to 

 all people, we may expect healthier, hap- 

 pier, more useful citizens. 



Questions 



1. State what is meant by the germ theory of disease. How old is the 

 theory? Which germ was first definitely associated with a human 

 disease? 



2. What connection is there between the industrial revolution and tuber- 

 culosis? Why did Koch's discovery of the germ help to reduce the 

 death rate of tuberculosis? 



