RECENT ADVANCES IN SCIENCE BEARING ON MEDICINE. 577 



tious diseases, the latter of which is determined by the reaction of the 

 tissues and organs to microbes. Secondly, there is the relation between 

 the smaller parasites and the diseases determined by them. This may 

 be summed up in the general word (introduced by Professor Virchow 

 himself) "infection." But to assume that all infections result from the 

 action of bacteria is to go beyond the domain of present knowledge, 

 and probably to retard further progress. The third point is the ques- 

 tion as to the mode of action of infection. It is only the larger parasites 

 whose main effect is the devouring of parts of their hosts ; the smaller 

 act mainly by the secretion of virulent poisons. The recognition of this 

 latter fact has led to the brilliant work of Lister on the one hand and 

 to the introduction, of serum therapeutics on the other. 



ANTISEPTIC SURGERY. 



It would be carrying coals to Newcastle were I to sketch in London 

 the beneficial effects which the application of methods of cleanliness 

 has exercised upon surgical practice. In the city wherein the man still 

 lives and works who, by devising this treatment has introduced the 

 greatest and most beneficent reform that the practical branches of 

 medical science have ever known, everyone is aware that Lord Lister, 

 on the strength of his original reasoning, arrived at practical results 

 which the new theory of fermentative and septic processes fully con- 

 firmed. Before anyone had succeeded in demonstrating by exact 

 methods the microbes which are active in different diseases, Lister has 

 learned, in a truly prophetic revelation, the means by which protection 

 against the action of putrefactive organism can be attained. The open- 

 ing up of further regions of clinical medicine to the knife of the surgeon 

 and a perfect revolution in the basis of therapeutics have been the con- 

 sequence. Lord Lister, whom I am proud to be able to greet as an old 

 friend, is already and always will be reckoued among the greatest 

 benefactors of the human race. May he long be spared to remain at the 

 head of the movement which he called into existence. 



ARTIFICIAL IMMUNISATION. 



It remains for me to say a word concerning the other great problem, 

 the solution of which the whole world is awaiting with anxious impa- 

 tience. I refer to the problem of immunity and its practical corollary, 

 artificial immunisation. It has already happened once that an English- 

 man has succeeded in applying this to the definite destruction of at least 

 one of the most deadly infectious diseases. Jenner's noble discovery 

 has stood its trial as successfully, except in popular fancy, as he hoped. 

 Vaccine is in all hands; vaccination is, with the aid of governments, 

 spreading continually. Pasteur also labored with determination ; others 

 have followed him, and the new doctrine of antitoxines is continually 

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