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 us 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 Eue 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 Chimie et de Physique, 1862, vol. Ixiv., p. 22. Since that time the 
illustrious perpetual secretary of the Academy of Sciences has Iia4 
good reason to revise this " counsel," 
