18821884 375 



as out of proportion to the fact they were supposed to rest on. 

 It seemed excessive to conclude from the existence of the acarus 

 of itch, visible to the naked eye or with the weakest magnifying 

 glass, the presence of microscopic parasites in the humours 

 of virulent diseases. . . . Such hypotheses can be considered 

 but as a sort of intuition. >f 



"Hypotheses," said Pasteur, "come into our laboratories 

 in armf uls ; they fill our registers with projected experiments, 

 they stimulate us to research and that is all." One thing 

 only counted for him : experimental verification. 



Paul Bert, in his very complete report, quoted Huxley's 

 words to the Eoyal Society and Pitt's words to the House of 

 Commons. He stated that since the first Bill had been voted, 

 a new series of discoveries, no less marvellous from a theo- 

 retical point of view and yet more important from a practical 

 point of view, had come to strike the world of Science with 

 astonishment and admiration." Eecapitulating Pasteur's 

 works, he said 



"They may be classed in three series, constituting three 

 great discoveries. 



' ' The first one may be formulated thus : Each fermentation 

 is produced by the development of a special microbe. 



" The second one may be given this formula : Each infec- 

 tious disease (those at least that M. Pasteur and his immediate 

 followers have studied) is produced by the development within 

 the organism of a special microbe. 



" The third one may be expressed in this way : The microbe 

 of an infectious disease, cultivated under certain detrimental 

 conditions, is attenuated in its pathogenic activity ; from a virus 

 it has become a vaccine. 



"As a practical consequence of the first discovery, M. 

 Pasteur has given rules for the manufacture of beer and of 

 vinegar, and shown how beer and wine may be preserved against 

 secondary fermentations which would turn them sour, bitter or 

 slimy, and which render difficult their transport and even their 

 preservation on the spot. 



" As a practical consequence of the second discovery, M. 

 Pasteur has given rules to be followed to preserve cattle from 

 splenic fever contamination, and silkworms from the diseases 

 which decimated them. Surgeons, on the other hand, -have 

 succeeded, by means of the guidance it afforded, in effecting 

 almost completely the disappearance of erysipelas and of the 



