1006 



SCIENCE. 



[N. S. Vol. XVI. No. 417, 



point, with facts acquired by ingenious 

 experimentation, with the ultimate result 

 of giving to the doctrine of spontaneous 

 generation its death blow. 



Fermentation and spontaneous genera- 

 tion prepared Pasteur for his next' victory. 

 The French wine trade was threatened 

 with disaster. Wines prepared hy the 

 accepted methods often became sour, bit- 

 ter or ropy. It was said that they- suffered 

 from diseases, and the situation was crit- 

 ical. It was Pasteur's achievement not 

 only to prove that the diseases were fer- 

 mentations, caused not spontaneously but 

 by microscopic germs, but also to suggest 

 the simple but effective remedy of heating 

 the bottles and thus destroying the offend- 

 ing organisms. 



It seemed a long step from the diseases 

 of wines to the diseases of silkworms, yet 

 when a serious epidemic, killing the worms 

 by thousands, threatened irreparable injury 

 to the silk industry, it was only natural 

 that Pasteur, with his growing reputation 

 for solving mysteries by the diligent appli- 

 cation of scientific method, should be called 

 upon to aid. He responded with his cus- 

 tomary enthusiasm, and for five years dili- 

 gently sought the cause of the trouble and 

 the cure. Though stricken by paralysis 

 in the midst of his work, in consequence 

 of which for a time his life hung in the 

 balance, in three months he was again in 

 his laboratory. Here, as in his previous 

 labors, he achieved final success. He 

 proved that the silkworms were infested 

 with distinct diseases, due to easily recog- 

 nizable germs. Furthermore, he devised 

 efficient methods of eliminating the dis- 

 eases, and thus he relieved from its pre- 

 carious condition the silk industry of 

 France and of the world. 



By the year 1870 Pasteur's success had 

 already assured him, at less than fifty 

 years of age, a commanding place in the 

 scientific world. His demonstrations of 



the all-important parts played by micro- 

 scopic organisms in the phenomena which 

 he had studied, had stimulated widespread 

 investigation. He had already dreamed 

 of the germinal nature of human diseases ; 

 and now medicine, which had long sus- 

 pected them to be associated with fermen- 

 tation processes, began to appreciate the 

 significance of the new discoveries. In 

 1873 he was elected to fill a vacancy in the 

 French Academy of Medicine, and from 

 that time on he gave more exclusive atten- 

 tion to pathological phenomena. He in- 

 vestigated septicemia, puerperal fever, 

 chicken cholera, splenic fever, swine fever, 

 and lastly rabies. To speak at length of 

 what he accomplished in this field would 

 require much time. I would, however, 

 mention one salient incident. 



One day chance revealed to him a unique 

 phenomenon, the further study of which 

 led to one of his most significant discov- 

 eries. In the inoculation of some fowls 

 with chicken cholera, not having a fresh 

 culture of the germs, he used one that had 

 been prepared a few weeks before. To 

 his surprise, the fowls, instead of succumb- 

 ing to the resultant disease, recovered, and 

 later proved resistant to fresh and virulent 

 germs. This was the origin of the preg- 

 nant idea of the attenuation, or weaken- 

 ing, of virus, which, nearly a hundred 

 years before, Jenner unknowingly had 

 demonstrated in his vaccinations against 

 smallpox, and which had been employed 

 by physicians in all the intervening time. 

 By various methods of attenuation Pasteur 

 succeeded in producing vaccines from the 

 virus of several diseases, and he perfected 

 the process of vaccinating animals and 

 thus protecting them from attacks of the 

 disease in question. 



The story of Pasteur's brilliant investi- 

 gations of hydrophobia is too recent and 

 too well known to relate here. They form 

 a fitting ending to a life rich in scientific 



