VACCINATION. 737 



ticed in fairly ancient times by rather primitive Discovery of 

 races, and that Lady Mary Wortley Montague 

 introduced this method into Europe in 1718. 

 This was not the vaccination in vogue to-day, 

 however, but rather the inoculation of virulent 

 virus from the pustules of the diseased into the 

 healthy. As mentioned in one of the earlier chap- 

 ters, this procedure commonly produced a mild 

 type of disease (variola inoculata) which ren- 

 dered the individual immune to virulent small- 

 pox. 



Everyone knows that the vaccination of to-day, 

 i. e., the substitution of the virus of cowpox for 

 that of smallpox, was the discovery of Jenner 

 (1798), and we need offer no comments concern- 

 ing its efficacy nor repeat the well-earned epithets 

 which have been applied to the rare species of dis- 

 believers. Nothing is more certain than that 

 smallpox has ceased to be a world pest only be- 

 cause of the continued Jennerization of the race. 



The essential points established by Jenner are 

 the following: 1. That the vaccine disease 

 casually communicated to man has the power of 

 rendering him insusceptible to smallpox. 2. That 

 the specific cowpox alone, and not other eruptions 

 affecting the cow which might be confounded with 

 it, has this protective power. 3. That the cow- 

 pox may be communicated at will from the cow to 

 man, by the hand of the surgeon, whenever the 

 requisite opportunity exists. 4. That the cowpox, 

 once engrafted on the human subject, may be con- 

 tinued from individual to individual by successive 

 transmissions, conferring on each the same im- 

 munity against smallpox as was produced in the 



