VACCINATION 



2.->l 



of America and killed thousands of the Indians. It also 

 visited the colonies. In 1721, Boston was ravaged foi 

 the sixth time by this disease. Out of the 10,567 Inhabit- 

 ants, 5989 had the disease and 894 died. 



In 179G, Jenner, an Englishman, demonstrated the fact 

 that by inoculation of a person with cowpox, a disease 

 peculiar to cows and in some way allied to smallpox, the 

 patient would become immune to the dreaded disease. 

 This was one of the greatest and 

 most beneficial discoveries of medi- 

 cine which has ever been made. 



By the result of vaccination small- 

 pox has become a rare disease in the 

 civilized nations of the world, and is 

 least prevalent where the vaccination 

 laws are the most stringent. 



Vaccination for smallpox consists 

 in the inoculation of the human 

 patient with vaccine, a substance 

 secured from a cow sufferings from 



O 



cowpox. This usually causes a 



slight illness, but during the illness the patient acquires 

 a power which enables him to resist the germs of small- 

 pox. This acquired power of resistance is called im- 

 munity. 



Many people do not understand the theory of vaccina- 

 tion and its advantages, and have opposed its use through 

 fear of acquiring lockjaw from the vaccine. It has been 

 established that proper vaccine matter never contains 

 the germs of lockjaw, and if this disease occurs, ii is 

 due to failure in keeping the arm clean during the period 

 when the vaccination scar is forming. 



Immunity to disease is now being produced through 

 inoculation. The patient is inoculated, that is, there is 



Figure 250. — Bacteria 

 and Mold. 



One tenth of the num- 

 ber carried by one house 

 fly. 



