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covered tlie existence of a bacillus in tubercular matter, whicb. 

 can be distinguished from all other micro-organisms, except 

 that of leprosy, by its retention of aniline dye when submitted 

 to processes which discharge the colour from other Bacteria. 

 This bacillus can be cultivated, and if a drop of the culture 

 fluid is inoculated into animals they soon succumb, and 

 tubercle is found in all parts of their internal organs. These 

 observations have been repeated all over the world, and the 

 fact may now be considered as established, i can but hint at 

 the great changes which this discovery must bring about in the 

 diagnosis and treatment of tubercular disorders. I shall have 

 an opportunity presently of showing you a group of these 

 bacilli found in a particle of expectoration from a consumptive 

 patient in the Adelaide Hospital. The demonstration will h& 

 made after Koch's method, and with the illumination he so 

 strongly insists on. 



We must hasten on. What wdll be the practical issue of 

 these discoveries ? If it be established that every infectious- 

 disease has its own peculiar germ on which its existence de- 

 pends, we have gained for the first time in the history of 

 medicine a clue to these diseases. We get rid of the fogs of 

 speculation and come into the light. We know at least in 

 what direction to work in order to stamp out the enemy. Al- 

 ready some promise of this is being given. I w^as a member of 

 the International Medical Congress in London when Pasteur 

 startled us with the announcement that he had discovered and 

 put to the test methods of attenuating the virus of more than 

 one infectious disease, whereby he could safely vaccinate — as 

 he chose to call it — animals so as to protect them from future 

 attack. The evidence he adduced was based chiefly on experi- 

 ments with the bacilli of anthrax. He had found that the 

 bacillus ceased to grow in sterilized liquids at about 112% 

 although the cultivation was easy at about 107°. At this latter 

 temperature no spores are produced. By regulating the time 

 as well as the temperatures he obtained bacilli with different 

 degrees of virulence, and vaccination with the lower degree- 

 protected animals from infection by the higher. At length ha 

 obtained an attenuated virus which could be safely used for 

 protective purposes. This was an important discovery for 

 Prance, where it is stated more than twenty million (" plus de 

 vingt millions d'animaux") animals are affected with anthrax 

 annually. The first experiment was made on fifty sheep — twenty- 

 five were vaccinated and the other twenty-five not vaccinated. A 

 fortnight after the vaccination all of them were inoculated 

 with anthrax virus — the twenty-five vaccinated sheep escaped, 

 the other twenty-five died. The success of the experiment was- 

 so marked that Pasteur and his assistants vaccinated iu the 



