The Protection of Health 605 



dangerous, producing a genuine but generally mild type of 

 smallpox, it was preferable to loss of eyesight or life through a 

 severe attack. By 1796 Edward Jenner had successfully 

 proved by experiments that vaccination with the virus from 

 cattle afflicted with cowpox causes a local and mild develop- 

 ment of the disease, in the course of which defensive substances 

 which give active immunity to smallpox for a number of years 

 are produced in the blood. This method eliminated the risks 

 incurred by the older practice, and at the same time greatly 

 reduced the ravages of smallpox. Vaccination, if made universal 

 and compulsory, would eliminate entirely this loathsome disease. 



The discoveries of Jenner and later those of Pasteur have 

 brought about a revolution in preventive medical practice. 

 The use of vaccines, antitoxins, and similar biological products 

 is increasing constantly. Vast quantities of such products 

 are annually prepared under the most exacting and hygienic 

 requirements and are distributed through public and private 

 dispensaries. Inasmuch as all products must be pure, specific, 

 and have a definite potency, their production and distribution 

 were put by Congressional act under Federal control and 

 assigned to the Treasury Department which acts under the 

 Public Health and Marine Hospital Service. Constant super- 

 vision of manufacture and thorough testing at practically 

 every point in their distribution insure a dependable and safe 

 product. 



Vaccines result in active immunity and are used most com- 

 monly for smallpox and typhoid fever for man, and anthrax 

 for animals. During the year 1914 more than 100,000 persons 

 and in 1917 nearly ten times this number were immunized by 

 typhoid vaccination under the direction of the United States 

 Public Health Service. Typhoid vaccination is as simple in 

 performance as smallpox vaccination and produces no ill 

 results. Vaccination is sometimes used against cholera and 

 bubonic plague. New vaccines are being tried and may even- 

 tually come into common use. 



