122 I'AS'fEUK, ON SPONTANEOUS GENERATION* 



less of" the precautio}is taken to avoid tlie accidental introduc- 

 tion of foreign dust, compel tlie admission that if the flasks 

 Avere opened or closed in the vaults, without the oporator be- 

 ing obliged to carry them thence, the air in the vaults would 

 invariably prove to be as inactive as air heated to the tempera- 

 ture of red-hot iron. This does not arise, however, from the 

 circumstance that the air itself, and owing to the conditions 

 under which it is placed, has a special inactivity. On the 

 contrary, it being saturated with moisture, and the lower 

 organisms not requiring light for their existence, this air has 

 always appeared to the author more fitted than that on the 

 surface of the ground for the development of those organisms. 



In conclusion, we find that the ordinary atmospheric air 

 only here and there, and Avithout any constancy, presents the 

 conditions necessary for the first existence of the so-termed 

 spontaneous generations. In one situation germs exist; close 

 by, none at all ; at a greater distance, some of a different kind. 

 They are abundant, or the reverse, according to the locality, 

 llain lessens their number. In summer, after a succession of 

 fine days, they abound ; and in places v/here the atmosj)herc 

 has been perfectly calm for a long time, the germs are entirely 

 absent, and putrefaction does not take place, at any rate in 

 the liquids upon Avhich the author has experimented. 



But how is it, it may be asked, that in Gay-Lussac's expe- 

 riments Avith grapes, Toriila cf'/nv's?'*© is produced by the intro- 

 duction of a A'ery minute quantity of air ;= and that if the same 

 experiment be repeated Avitli dift'erent infusions, avc see these 

 undergo decomposition in contact Avith the smallest possible 

 quantities of air, and more than that, on the introduction of air 

 liat has been heated or artificially made -, for the experiments 

 of M. Pouchet in the mercurial bath are exact, whilst those of 

 SeliAvaiui, of the same nature, are almost always erroneous? 

 This arises simply from the circumstance that the mercury 

 itself is profusely filled Avith germs. This fact the author has 

 already stated Avith reference to experiments Avhich will be 

 detailed in his memoir ; but in the present communication he 

 contents himself Avitli giving a proof of this assertion which, 

 he says, Avill astonish every one. 



He takes some mercm'v Avhich is poured without any par- 

 ticular precautions into the bath, in any laboratory ; and, in 

 the mode described in a former part of his memoir, he intro- 

 duces, in the midst of an atmosphere of air Avhich had been 

 heated to redness, a single globule of this mercury, about the 

 size of a pea, into the decomposable liquid. Two days after- 

 wards, in every experiment he has made, organisms of various 

 kinds have been produced. But if the same experiments be 



