IN THE AIR THERE ARE LIVING GERMS 97 



this remains in the neck (Fig. 11), the liquid of the flask 

 retains its first clarity. At the end of 15 days, or a 

 month, we make the cotton fall into the infusion by 

 simply inclining the flask, and we shall see that at the end 

 of 24 hours, the liquid will become clouded, and that 

 after 48 hours it will contain millions of living organisms. 

 When birth is given there to cryptogamic growths, we 

 shall often see tufts of filaments growing out around 

 the cotton of the plug, testifying thus to their affiliation 

 with the germs which it contained. 



"What reply will you make to this experiment? The 

 microscope has shown us in the bit of 

 cotton substances of an amorphous 

 aspect and substances with an organ- 

 ized aspect. This we can affirm as a - 

 result of our first experiment. The $,. n Flask used 

 second, which I have just described, b y Pasteur in Ms study 



of fermentations and 



tells us that among the substances of the distribution of 

 on the cotton there are some that are e h r e in the atm 

 living. You partisans of spontaneous 

 generation, you are condemned to seek by preference 

 in amorphous and dead substances the enigma of the 

 life which appears in the infusions. Behold the in- 

 consequence into which my experiments drive you, 

 for, mark it, they are no longer doubtful, irregular, 

 contingent experiments, but they succeed 100 times in a 

 100, provided a little skill is used in performing them. 

 They are obedient to the mind as though following to the 

 letter the excellent program drawn up by the Academy of 

 Sciences: 'They are freed from all uncertainty arising 

 from the experiments themselves.' Repeat them with 

 the details which I give you and you will succeed just 

 as I have done." 



One can divine the effect of an argument so concise, 

 and having the charm of.a geometrical demonstration. 



