RESEARCH IN MEDICINE 9 



lately free from atmospheric air, and into which, therefore, no germ or 

 organic bodies could have been brought by the air " ; the latter insisting 

 that only through the entrance of such living organisms could the 

 changes in question take place. The discussion lasted several years, 

 and to-day presents many interesting details, but it may suffice to state 

 that it was ended by Pasteur's demonstration that if the neck of a flask 

 was drawn out into a fine tube and bent into a double curve and the 

 flask then heated by boiling, no decomposition occurred. The flask was 

 open to the atmospheric air, but the microorganisms of the air were 

 arrested by the drop of water of condensation, in the lower point of the 

 curved neck. This demonstration, with the later work of Cohn on 

 spores and of Tvndall on floating matter in the air, disposed of the 

 doctrine of spontaneous generation and led to the universal acceptance 

 of Harvey's law Omne vivum ex ovo, or as it was modified, Omne 

 vivum ex vivo. 



It is not surprising that Pasteur at this time foresaw the possibili- 

 ties in the study of the etiology of the infectious diseases. The process 

 of fermentation, due to living microorganisms, and beginning with a 

 period of apparent inactivity, passing on to a stage of very evident ac- 

 tivity and finally sinking gradually into quiescence, was analogous to 

 the period of incubation, the stage of active manifestations and the 

 gradual defervescence of an infectious disease. Also the specificity of 

 the ferments was evidently suggestive of the specific etiology of dis- 

 ease, and altogether we see from several of Pasteur's statements at this 

 time that the relation of microscopic organisms to disease occupied his 

 mind. Thus in a letter to his father, in 1860, he expressed the hope 

 that he may, "bring a little stone to the frail and ill-assured edifice of 

 our knowledge of those deep mysteries of Life and Death where all our 

 intellects have so lamentably failed " and in 1863, after an audience 

 with Napoleon III., he writes, " I assured the Emperor that all my am- 

 bition was to arrive at the knowledge of the causes of putrid and con- 

 tagious diseases." 



And now with that peculiar trick of coincidence that is so surprising 

 in the course of culture and inquiry, we find that about this time bac- 

 teriology began to make advances along three general lines of study: 

 (1) The etiology of the acute infectious diseases; (2) the prevention 

 of infection, and (3) the achievement of cure or immunity by vaccina- 

 tion. In the first and third of these, Pasteur played a prominent part 

 and it was his work on fermentation which suggested the second to 

 Lister. Pasteur's entrance into the field of etiology and the results he 

 there accomplished form one of the most interesting phases of the his- 

 tory of science and its outcome, a matter of the greatest economic im- 

 portance to France. The opportunity to study an infectious disease 

 was offered by an epidemic of a mysterious disease which was ruining 



