568 FRAGMENTS OF SCIENCE. 



viction with which he began it, and landed him in down- 

 right credulity in the end. I do not question his ability as 

 an observer, but the inquiry needed a disciplined experi- 

 menter. This latter implies not mere ability to look at 

 things as Nature offers them to our inspection, but to force 

 her to show herself under conditions prescribed by the 

 experimenter himself. Here Pouchet lacked the necessary 

 discipline. Yet the vigor of his onset raised clouds of 

 doubt, which for a time obscured the whole field of 

 inquiry. So difficult indeed did the subject seem, and so 

 incapable of definite solution, that when Pasteur made 

 known his intention to take it up, his friends Biot and 

 Dumas expressed their regret, earnestly exhorting him to 

 set a definite and rigid limit to the time he purposed 

 spending in this apparently unprofitable field.* 



Schooled by his education as a chemist, and by special 

 researches on the closely related question of fermentation, 

 Pasteur took up this subject under particularly favorable 

 conditions. His work and his culture had given strength 

 and finish to his natural apitudes. In 1862, accordingly, 

 he published a paper " On the Organized Corpuscles exist- 

 ing in the Atmosphere/' which must forever remain 

 classical. By the most ingenious devices he collected the 

 floating particles of the air surrounding his laboratory in 

 the Rue d'Ulm, and subjected them to microscopic 

 examination. Many of them he found to be organized 

 particles. Sowing them in sterilized infusions, he obtained 

 abundant crops of microscopic organisms. By more refined 

 methods he repeated and confirmed the experiments of 

 Schwann, which had been contested by Pouchet, Monte- 

 gazza, Joly, and Musset. He also confirmed the experi- 

 ments of Schroeder and Von Dusch. He showed that the 

 cause which communicated life to his infusions was not 

 uniformly diffused through the air; that there were aerial 

 interspaces which possessed no power to generate life. 

 Standing on the Mer de Glace, near the Montanvert, he 

 snipped off the ends of a number of hermetically sealed 

 flasks containing organic infusions. One out of twenty of 



* " Je ne conseillerais a personne," said Dumas to his already 

 famous pupil, " de rester trop longtemps dans ce sujet." Annales 

 de CJiimie et de Physique, 1862, vol. Ixiv., p. 22. Since that time the 

 illustrious perpetual secretary of the Academy of Sciences has had 

 good reason to revise this " counsel." 



