314 FRAGMENTS OF SCIENCE 



hood of argumentative assertion was sure to influence 

 minds swayed not by knowledge, but by authority. Had 

 Pouchet known that " the blue ethereal sky" is formed of 

 suspended particles, through which the sun freely shines, 

 he would hardly have ventured upon this line of argu- 

 ment. 



Pouchet' s pursuit of this inquiry strengthened the con- 

 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 ex- 

 perimenter. 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 nec- 

 essary discipline. Yet the vigor of his onset raised clouds 

 of doubt, which for a time obscured the whole field of in- 

 quiry. 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. 1 



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 aptitudes. In 1862, accordingly, 

 he published a paper "On the Organized Corpuscles exist- 



1 **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 had good reason to revise this "counsel." 



