THE STORY OF NINETEENTH-CENTURY SCIENCE 



All advances in science have a bearing, near or re- 

 mote, on the welfare of our race ; but it remains to 

 credit to the closing decade of the eighteenth century a 

 discovery which, in its power of direct and immediate 

 benefit to humanity, surpasses any other discovery of 

 this or any previous epoch. Needless to say I refer to 

 Jenner's discovery of the method of preventing small- 

 pox by inoculation with the virus of cow-pox. It de- 

 tracts nothing from the merit of this discovery to say 

 that the preventive power of accidental inoculation had 

 long been rumored among the peasantry of England. 

 Such vague, unavailing half-knowledge is often the fore- 

 runner of fruitful discovery. To all intents and purposes 

 Jenner's discovery was original and unique. Neither, 

 considered as a perfected method, was it in any sense an 

 accident. It was a triumph of experimental science; 

 how great a triumph it is difficult now to understand, for 

 we of to-day can only vaguely realize what a ruthless and 

 ever-present scourge small-pox had been to all previous 

 generations of men since history began. Despite all 

 efforts to check it by medication and by direct inocula- 

 tion, it swept now and then over the earth as an all- 

 devastating pestilence, and year by year it claimed one- 

 tenth of all the beings in Christendom by death as its 

 average quota of victims. " From small-pox and love 

 but few remain free," ran the old saw. A pitted face 

 was almost as much a matter of course a hundred years 

 ago as a smooth one is to-day. 



Little wonder, then, that the world gave eager ac- 

 ceptance to Jenner's discovery. The first vaccination 

 was made in 1796. Before the close of the century the 

 method was practised everywhere in Christendom. No 

 urging was needed to induce the majority to give it 



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