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departments near to Paris, iu a fortnight, 20,000 slieep and a, 

 large number of cattle. There is no reason to doubt Pasteur's 

 success in these experiments. It is, however, to be regretted 

 that other experimenters, and particularly Klein in England, 

 have not met with the same success in their attempt to follow 

 Pasteur's mode of preparing his attenuations, nor have the 

 attenuations prepared by Pasteur himself proved in Klein's 

 hands to be so protective as was at first anticipated. It has 

 been suggested that there are conditions necessary to cer- 

 tain success which even the great French chemist has not 

 quite mastered ; but that there is a basis on which to work 

 no one who listened to Pasteur's address can doubt. I 

 may mention here a remarkable discovery of Klein's, made 

 while engaged on his anthrax experiments. This observer 

 found that although he failed to confirm Pasteur's results, he 

 could protect sheep against virulent anthrax by passing the 

 virus through a mouse. If the blood of a mouse dead from 

 anthrax were inoculated into a sheep there was a slight rise of 

 temperature, but no further development of disease ; and some 

 sheep thus treated, and afterwards inoculated with strong 

 virus four times in succession, remained free from harm. This 

 is analogous to the attenuation of smallpox virus by the inocu- 

 lation of a cow — a discovery by Jenner — which in our own 

 times has done more for the human race than any other dis- 

 covery of modern times. Is it not probable that what is true 

 of smallpox and of anthrax may be true of all the other infec- 

 tious diseases, and that steady research may enable us to attenu- 

 ate the virus of all of them so as to obtain complete immu- 

 nity ? The tendency of discovery is in this direction. Pasteur 

 is again to the front. Only a mail or two ago we got in- 

 telligence that after some four years' work he was able 

 to announce that he had succeeded in attenuating the virus 

 of that most intractable and most horrible of all infec- 

 tious diseases hydrophobia, and that with this attenuated 

 virus he could prevent animals bitten by rabid dogs being 

 infected. He demonstrated this before a Commission in 

 Prance by experiments on 38 dogs. Of these 19 were vac- 

 cinal ed with the attenuated virus, and all of them were 

 t<hown to be proof agaiiist infection. Of the other 19 not vac- 

 cinated, six were bitten by rabid dogs, and three of them be- 

 came mad ; and of the others inoculated by injection of virus 

 all became mad except two. The mode of attenuating the 

 virus in these experiments is different from that employed in 

 anthrax. It resembles that of Jenner for smallpox, and o£ 

 Klein for anthrax. Pasteur found that the virus passed 

 through some animals — rabbits and guinea pigs — increased in 

 virulence, but on its being passed through monkeys it became 



