VACCINATION. 5 



what he had learned about fermentations to the 

 study of the diseases of wines and beers. He found 

 their causes, and devised a preventive measure, 

 which consisted merely in the destruction of the 

 germs by heating the wine to a suitable tempera- 

 ture before it was stored. At the instance of the 

 French government, he then studied certain dis- 

 eases of silkworms. His success in discovering 

 their causes and prevention must always remain for 

 us one of the landmarks of the world's progress. 

 It was during the latter investigations that he 

 took up the study of anthrax. The specific mi- 

 crobe having been discovered, and the methods of 

 transmission of the malady having been made 

 clear through investigations by both Pasteur and 

 Koch, Pasteur turned his attention to methods 

 of prevention and, if possible, of cure. 



Pasteur pondered the question of smallpox vac- 

 'cination. He came to believe that vaccinia is 

 smallpox, the virus of which has been attenuated 

 by its passage through the cow, and that conse- 

 quently when man undergoes vaccination he there- 

 by is inoculated with a benign form of the disease. 

 Might not this be an example of a law which would 

 be general in its application ? The protective inoc- 

 ulation (active immunization) against the pleuro- 

 pneumonia of cattle which had long been prac- 

 ticed gave encouragement to this hope. Some 

 work by Toussaint was important in the answer 

 to this question. It was evident that a weakening 

 or attenuation of the bacteria or virus must first 



souring of milk, now the formation of butyric acid in sauer- 

 kraut, now the fermentation of wine, now the decomposition 

 of albuminous matters, now the splitting up of urea, now 

 the red color of starchy food, and give rise now to diphtheria, 

 now to typhoid fever, now to recurrent fever, now to 

 cholera, now to malarial fever.' " (Cited from Hektoen, in 

 Osier's System of Modern Medicine, Vol. I.) 



