A HISTORY OF SCIENCE 



enough, the unbelievers struck their colors and sur- 

 rendered without terms; the principle of protective 

 vaccination, with a virus experimentally prepared in 

 the laboratory, was established beyond the reach of 

 controversy. 



That memorable scientific battle marked the begin- 

 ning of a new era in medicine. It was a foregone con- 

 clusion that the principle thus established would be 

 still further generalized; that it would be applied to 

 human maladies ; that in all probability it would grap- 

 ple successfully, sooner or later, with many infectious 

 diseases. That expectation has advanced rapidly tow- 

 ards realization. Pasteur himself made the applica- 

 tion to the human subject in the disease hydrophobia 

 in 1885, since which time that hitherto most fatal of 

 maladies has largely lost its terrors. Thousands of 

 persons bitten by mad dogs have been snatched from 

 the fatal consequences of that mishap by this method 

 at the Pasteur Institute in Paris, and at the similar in- 

 stitutes, built on the model of this parent one, that have 

 been established all over the world in regions as widely 

 separated as New York and Nha-Trang. 



SERUM-THERAPY 



In the production of the rabies vaccine Pasteur and 

 his associates developed a method of attenuation of a 

 virus quite different from that which had been em- 

 ployed in the case of the vaccines of chicken cholera 

 and of anthrax. The rabies virus was inoculated into 

 the system of guinea-pigs or rabbits and, in effect, 

 cultivated in the systems of these animals. The spinal 

 cord of these infected animals was found to be rich in 



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