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Co?ista?it Care Is Needed for Health unit vi 



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Fig. 299 Death rate from diphtheria per 100,000 

 people in New York City. Co?/! pare the rates 

 of 1882 with 193';. Since which year has there 

 been a steady decrease? Why? (saunders) 



Fig. 300 The bacillus that causes tetanus (lock- 

 jaw) fornis a spore at one end of the cell. Of 

 what iynportance is this fact? (American mu- 

 seum OF NATURAL HISTORY) 



Testing for susceptibility to diphtheria. 



Some children seem to have a natural 

 immunity to diphtheria. In this respect 

 it is different from smallpox to which 

 none of us seems to be naturally immune. 

 Doctor Schick wanted to avoid unneces- 

 sary immunization. He therefore de- 

 vised a simple test now known as the 

 "Schick test." By means of this, the sus- 

 ceptible children can be discovered. 



A very small amount of toxin is in- 

 jected into the skin of the arm. After 

 about twenty-four hours a doctor can 

 tell from the appearance of the skin in 

 the region near the injection whether or 

 not the person is naturally immune. If a 

 peculiar red region appears, the results 

 are "positive," that is, the child is suscep- 

 tible, and the doctor recommends immu- 

 nization with toxoid. If the results are 

 negative, immunization is not necessary. 

 Immunization is a safe and cheap insur- 

 ance against diphtheria. And at the same 



time it helps to protect others in the 

 community. When every child is tested 

 for susceptibility and then immunized if 

 necessary, there will be less diphtheria. 



Antitoxin against lockjaw. Until re- 

 cently lockjaw or tetanus (tet'an-us), 

 like rabies, meant certain death. Unlike 

 most other pathogenic bacteria, the germ 

 that causes the disease can form a spore. 

 In this form it can live for a lon^ time 

 without the warmth and food of the ani- 

 mal's body. Tetanus spores may rest in 

 the soil; they are common in soil which 

 has been long under cultivation, particu- 

 larly if it has been fertilized with horse 

 manure. How do tetanus spores get into 

 the soil? The germ lives in the horse and 

 some other animals. Having entered 

 throucfh the mouth, it can live and re- 

 produce in the digestive tract without 

 giving any symptoms of the disease or 

 doing any harm to the animal. The 

 germs leave the animal's body in large 



