THE GERM ORIGIN OF INFEC'l 20US DISEASES. 381 



is a specific infectious disease caused by a specific micro-organism which con sti- 

 tutes in fact the true tubercular virus." 



These views are opposed by some of the ablest men in the medical profession, 

 among them Dr. Formad, of Philadelphia, who admits the presence of the germs, 

 but believes they are the effect and not the cause of the disease ; the discussion 

 is still going on but the most distinguished pathologists of both hemispheres ac- 

 knowledge his discovery and accept his conclusions ; the veteran Austin Flint, 

 Sr. , of New York, being one of the number. At the last meetjng of the American 

 Medical Association at Washington, as its president, he announced his concur, 

 rence in Dr. Koch's discovery. 



But we must again turn to Pasteur, of France, who has taken another step 

 forward in this new field of study. Over four years ago he commenced his work 

 to discover the cause and prevention of hydrophobia; his past experience had led 

 him to believe that in the virus of many of the infectious diseases was to be found 

 the means to guard against the infection; that is to say — by introducing into the 

 body of a healthy animal by inoculation a similar, but attenuated virus, it will 

 prevent the danger of the infection when exposed to it. He commenced his ex- 

 periments in the following way : A monkey 'was selected and inoculated with 

 the microbe, or virus of a rabid dog; the animal died, he repeated the experi- 

 • ment by taking the virus from the dead monkey and inoculating a second one, 

 taking the virus from this second one he repeated it upon a third monkey, and 

 then found that it was almost innocuous; he then took the weak virus and inocu- 

 lated a rabbit, and found its power increased, this last was then used upon a 

 second rabbit, and he found its intensity still more increased, the virus from the 

 last was then used upon a third and fourth rabbit until it had reached its 

 greatest strength. With this modified virus, varying in degrees of strength, he 

 inoculated healthy dogs, then after a time exposed them to the bite of the rabid 

 animal, and found that the bite did not affect them; he then selected forty-two 

 healthy dogs, twenty-three of which were inoculated with this modified virus; 

 they were after a time allowed to be bitten by the rabid dog; not one of them 

 had the hydrophobia ; he now exposed the nineteen dogs that had not been pro- 

 tected by inoculation ; out of the number fifteen soon became rabid. After fully 

 satisfying himself as to its protective power, he made his report to the Academy 

 of Sciences at Paris, he also attended the meeting of the International Medical 

 Congress at Copenhagen, Denmark, and on the nth of last August that body 

 listened to his address, and he repeated the experiments leading to his discovery 

 in detail; the latest reports from Paris, recount his final and complete triumph. 

 A commission of seven members was appointed by the Academy of Sciences to 

 fully examine into the merits of his discovery; the commission repeated his exper- 

 iments, and have made their report, that he has succeeded in protecting against 

 the virus of hydrophobia. 



Now many, at first thought, may regard this discovery as of no great signifi- 

 cance, because so few persons are bitten by the rabid dog, but when we reflect 

 that it estabhshes a great law which further experimentation may show is appli^: 



