264 Jlppeitdix. 



hairs, coal-dust, etc., which are known to be floating in the at- 

 mosphere, numerous round or oval organized corpuscles, some of 

 which "closely resemble the spores of the commonest moulds." 

 and others "resemble the globular infusoria and are regarded as 

 being the eggs of these small beings." "But, as to affirming," 

 he says " that this particular one is a spore, or still more that it 

 is a spore of a definite species, or that that corpuscle is the Qgg of 

 an infusoria or of such a species, I do not believe that this is pos- 

 sible. I am content, as far as I am concerned, to affirm that 

 these corpuscles are evidently organized." In the light of Le- 

 maire's subsequent observations, which will soon be alluded to, 

 it is demonstrated that this opinion of Pasteur's was correct. 



Now assuming that such germs are floating in the atmos- 

 phere, Pasteur asserted that their number and variety would differ 

 greatly in given volumes of air collected from different locali- 

 ties, and he even said in definite terms " that everywhere it was 

 possible to detach a volume of air from the atmosphere which 

 will contain neither egg nor spore, and will not produce gener- 

 ation in putrescible solutions." To determine this point he pre- 

 pared a large number of flasks partly filled with solutions of su- 

 gar and yeast. After thorough boiling the flasks were hermeti- 

 cally sealed by drawing out the necks to a fine point. The flasks 

 were then taken to different localities and opened by pinching off 

 the necks. Air would rush in by reason of the partial vacuum 

 which had been formed by the boiling of the contained fluid, and 

 thus air from any locality could be gathered for experiment. In 

 this way air was taken from the tops of high mountains, in the 

 very midst of glaciers, from level, open plains in the country, 

 from the streets of crowded cities, from cellars, etc. The result 

 was that just in proportion to the distance from crowded cities, 

 and the absence of disturbing currents in the atmosphere, the 

 evidences of organic life diminished. Of twenty flask§ which were 

 opened on the ^'- Mer de Glace,'' in the Alps, at an altitude of 

 6,000 feet, one only subsequently contained any trace of life. In 

 another series of experiments flasks were filled in the cellars of 

 the Observatory in Paris, where the temperature is almost uni- 



