EASTEUKj ON SPONTANEOUS GENERATION. 121 



ahvavs reach the surface of a licjuid. placed whilst boiling in an 

 uncovered vessel, a quantity of air sufficient to convey to it 

 germs fitted to become developed in the liquid in the space of 

 two or three days. 



It lias been said that the organisms produced are more 

 varied in the flasks prepared as above than if the contact with 

 the atmosphere had been freer ; and nothing can be more 

 natural than that it shovdd be so. For when the quantity of 

 air admitted at one time is limited, and the admission is 

 repeated a immber of times, the atmospheric germs are 

 caught, as it Avere, in all the varieties under which they exist 

 in the air. 



The small number of germs contained in a limited quantity 

 of air are not hindered in their development by other germs, 

 either existing in greater numbers or gifted with a more 

 precocious fecundity, and capable of occupying the whole field, 

 and leaving no place but for themselves. It is for this reason 

 that Penicii/ium c/Iaucuni, whose spores are vivacious and 

 widely difl\ised, a])pears alone, at the end of a very few days, 

 in the same liquids not enclosed, which, when exposed to 

 limited quantities of air only, woidd, on the contrary, have 

 aflbrded a great variety of organisms. 



Lastly, the author cannot omit noticing the differeneeswhieh 

 are observed in the numl)er of negative results in these experi- 

 ments, according to the varying conditions of the atmosplicre; 

 a circumstance whick affords a striking confirmation of his 

 opinions. 



Nothing, in fact, is more easy than to augment or diminish 

 either the number of flasks in which organisms are produced, 

 or the number of flasks in which they shall be totally absent. 



The author confines himself to the relation of experiments 

 wliich he was enabled to undertake in the vaults of the Paris 

 Observatory. 



In this place, as the vaults are situated in the zone of equal 

 annual temperature, the perfectly calm air would evidently 

 allow every particle of dust to fall to the ground, in the 

 intervals of the disturbances which might be caused by the 

 movements of the observer, or by the objects introduced by 

 him. Consequently if every precaution be observed when the 

 experimenter enters the vault to procure portions of the air, 

 the number of flasks which will ultimately aftbrd no organisms 

 ought to be considerably greater than in the case where they 

 may have been filled, for example, with the air in the court of 

 the Observatory. This is what takes place; and the con- 

 clusions to be drawn from the results of experiment, from the 

 agreement it shows with nature, or the multiplicity greater or 



