164 BACTERIOLOGY FOB NURSES 



of cowpox (vaccina), inoculation had been prac- 

 ticed. It had been found that inoculation by scarify- 

 ing the skin and introducing a small amount of virus 

 from a smallpox pustule would usually result in a 

 mild attack of smallpox, with immunity from the 

 disease in the future; but this form of the disease 

 was as contagious as smallpox contracted in the 

 usual way, and not infrequently was of a serious, if 

 not fatal, type. 



In 1798 Jenner pubhshed an account of his dis- 

 covery that vaccination with the virus of cow- 

 pox produced only a sUght local infection and 

 conferred immunity from smallpox. Jenner had 

 observed that milkers were often infected through 

 abrasions upon the hands by the pustules of cow- 

 pox upon the cow's teats, and that they were hence- 

 forth immune from smallpox. The fact that vacci- 

 nation not only conferred immunity for several years, 

 but that the general symptoms produced were of the 

 mildest character and non-contagious, led to its 

 adoption in all civiUzed countries, which has resulted 

 in stamping out the frightful epidemics of smallpox 

 which were formerly common occurrences. 



Vaccination should always be done under the 

 strictest aseptic conditions: that serious secondary 

 infections have often occurred through vaccination 



