8z8 THE POPULAR SCIENCE MONTHLY. 



been almost universally recognized. The processes by which he has 

 arrived at his discoveries and the success which has attended his appli- 

 cation of them are best told in his own language, and are thus told in 

 his address before the recent International Medical Congress, which is 

 published in the present number of " The Popular Science Monthly." 

 This address, the " Westminster Review " says, " was as fascinating 

 in the unerring sequency of experiments as in the unbounded pros- 

 pects of preventive medicine foreshadowed, and the masterly unravel- 

 ing of some of Nature's most occult secrets." 



M. Pasteur in 1880 proposed the application of the method which 

 he used in seeking the cause of the silk-worm disease, to the detection 

 of a parasite destructive to the phylloxera, and its cultivation as an 

 antidote to that pest of the grape-vine. He said in a " programme for 

 researches," which he communicated to the Academy of Sciences, on 

 this subject, suggesting an inversion of the problem studied in the case 

 of the silk- worm : " Let us seek a parasite for the phylloxera species, 

 and, far from combating it, let us cause it to multiply and fasten upon 

 the phylloxera till it destroys it, as the pebrine parasitic corpuscle so 

 easily destroyed the silk-worms. . . . The rapid multiplication of the 

 phylloxera is only a trifle beside the vital and propagative power of 

 certain parasites. . . . The hall of the Academy of Sciences is very 

 large ; it has a capacity of hundreds of cubic metres. I am sure I could 

 fill it with a liquid of such a nature that, on planting in it a parasitic 

 microscopic organism of the fowl, the whole immense mass would, in 

 the course of a few hours, be troubled by the presence of the organism 

 in such abundance that all the phylloxeras in the world would be, in 

 number, only as a drop of water to the sea compared with the numbers 

 of the parasite of which I speak." 



Notwithstanding this, he is so confident of the efficiency of the 

 methods of treatment which his researches indicate, that he has been 

 able to say, in his work on the silk- worm disease, that " it is in the 

 power of man to make parasitic maladies disappear from the surface 

 of the globe, if, as is my conviction, the doctrine of spontaneous gen- 

 erations is a chimera." 



Another field of investigation, in which M. Pasteur has made a few 

 preliminary steps, is that of the transmission of human diseases by 

 microscopic organisms. He has now numerous co-laborers in these 

 fields, in England, France, Germany, and other nations, many of whom 

 have become famous through their researches, and who are extending 

 the range of investigation every day ; but he was the first to direct 

 attention to this branch, and is still the leader of the company. 



M. H. Bouley, speaking in the name of the Academy of Sciences, 

 before the annual meeting of the " Five Academies," said, in special 

 reference to M. Pasteur's work : " See how, at once, Nature has suffered 

 one of her most impenetrable secrets to be snatched from her the mys- 

 tery of contagions is unveiled ; and Science, enlightened by the knowl- 



