« 



298 



THE BEGINNINGS OF IIFE. 



filtered infusions exposed to the air beneath a bell-jar 

 had been derived from ova or from dried adult forms 

 which (after dropping into the infusion) had subse- 

 quently propagated themselves and multiplied therein 

 then such ova or dried adult forms ought to drop just 

 as freely into receptacles of distilled water presentino- 

 an equal area and similarly exposed. These ova or 

 dried animals are sufficiently large to be easily dis- 



coverable, when present; and 



placing the water 



or five days the surface of the organic infusion similarly 

 exposed beneath a bell-jar will have become covered 

 with a thick pellicle, and the infusion itself, if not 

 affording an acid reaction, may be found to contain an 



incalculable multitude of ciliated Infusoria, of one form 

 or another. 



come 



myriads of animalcules ? Can they have been derived 

 from certain germs floating in the limited atmosphere 

 to which the infusion has been exposed? If so, one 

 would think that it must be from a very limited 

 number, seeing that none are to be found in the 



I 



Moreover, 



ff 



idence 



of 



jl Pasteur a 



aJedlv lead 

 rtion of ail 



F 



after a time in a conical vessel, any particles which it 

 contains may be allowed to sink before the supernatant 

 fluid is slowly drawn off", either by a pipette, or, better j oftlieir germ 

 still, by a siphon of small bore. The microscopical | serais f corp 

 examination of the small quantity of fluid which re- 

 mains will very rarely show a trace of a ciliated In- 

 fusorium^ either adult or in the form of egg. And yet, 

 if the weather has been warm, in the course of four 



siz;, and are 



e the sp 



li much m( 

 oflnfi 



are abui 



met wit! 



? 



I 



of ord 



'Vin, the , 

 sccpist 



c 



at tlie 



Pelli 



K 



\ 



to be 



ior 



Un!es; 



4N h 



/ 



