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possessed in his time did not permit of its being 

 looked at in any further way than as a simple fact 

 or truth of nature. Viewed, however, with the 

 light that has been thrown upon it by the re- 

 searches of the present day, we see not only the 

 fact, but also its explanation — we see that the 

 principle of action of the procedure proposed by 

 Jenner, which has conferred such incalculable 

 benefit upon mankind, is based upon the attenu- 

 ating effect upon the small-pox virus of the human 

 species by transmission through another animal, 

 and knowing this the prospect is presented of its 

 being rendered susceptible of application for the 

 control of other diseases. Whether this should 

 prove so or not, at all events, advantage is gained 

 by the knowledge acquired. 



Need I say anything more to exhort you in 

 accordance with the duty that has devolved upon 

 me ? Surely the acquirement of knowledge, giving 

 us as it does greater power in the exercise of our 

 calling, and thereby promoting the high and noble 

 object of rendering our lives more useful to our 

 fellow-creatures — surely this is a sufficient in- 



