INTRODUCTION 11 



bassador to Constantinople, permitted her son to be 

 inoculated against smallpox with the matter from 

 variola pustules and subsequently, in 1721, introduced 

 the method in England. Despite the brilliant results 

 that followed, the practice encountered bitter opposi- 

 tion, owing to the fact that although it protected the 

 inoculated it did not prevent conveyance of the disease 

 in a virulent form to the uninoculated, and was finally 

 prohibited by law. 



Sixty years later, the attention of Jenner was di- 

 rected to a peculiar disease of the udders of cows, from 

 which the hands of milkmen became infected, render- 

 ing them immune to smallpox. Jenner investigated 

 the subject for a number of years, and in 1796 in- 

 oculated a boy with " cow-pox," after which inocula- 

 tion with smallpox showed him to be immune. Two 

 years later, in 1798, Jenner published his classical re- 

 port, which was soon followed by systematic and uni- 

 versal vaccination against the world's greatest scourge. 

 Although the causative organism in the virus of small- 

 pox has not been discovered, even to this day, Jenner 

 firmly established the doctrine that it is possible to con- 

 fer immunity against an infectious disease by the em- 

 ployment of a modified materies morhi. 



Almost a century passed before any further not- 

 able advance occurred in immunology. Indeed it re- 

 quired the stimulus of the era of bacteriology to pro- 



