1 T. P. ANDERSON STUART. 



tralian Governments in the matter of the discoveries 

 announced by Dr. Koch in that year, I saw Koch on the 

 subject, in which he was much interested ; and in the 

 previous year I had also seen Pasteur. Bearing in mind 

 how often some contagious disease sweeps away whole 

 hutchfuls of rabbits in confinement, they both believed that 

 a microbe might one day be " caught " which would prove 

 fatal to the rabbits, and being a living organism, would 

 spread from animal to animal. Granting, however, that 

 this did happen, it by no means follows that the rabbits 

 would in this way be exterminated in the open ; and yet 

 I am afraid that this has been the idea and hope of many 

 people on the subject. The fact is, that disease organisms 

 do not act in that way. Being parasites, if they were to 

 kill off the animals on which they live, how would they 

 themselves survive ? For instance — the plague microbe 

 infects rats, but rats unfortunately are by no means 

 exterminated in any district. Again, take small-pox — ■ 

 probably, but not proved to be, of microbial origin — what 

 could be more virulent in an unvaccinated community, and 

 yet the peoples have survived. And so it is with every 

 other disease of microbial origin. Accordingly, even if 

 fully successful, one must not expect too much from the 

 Danysz experiment. This microbe won't spread and spread 

 until all the rabbits are killed off. It will in given regions 

 lose its virulence, and rabbits immune to its influence will 

 remain ; and so, in any case, supply-stations would be 

 needed all over the country, where the cultures would 

 be kept up in virulence, and wiience ever new supplies 

 would necessarily be sent out. The experiments with 

 the Danysz rat microbe, to be presently referred to, 

 have a direct and very important bearing upon this aspect 

 of the rabbit experiments. Altogether, the process is not 

 quite simple, and yet it was well worth the experiment, 

 for the suggestion once having been made the public would 



