Chap, i.] ON THE ORIGIN OF OKGANISED BEINGS. 805 



very exceptionally that we find the ovum of a ciliated microzoon 

 or the spore of a mucedinate. 



If, by the help of an eight-horse motive power, we project on 

 diverse macerations of plants 6 milliou litres of that atmospheric 

 air wMch is said to be full of germs, we see that the macera- 

 tions, exposed to this torrent of ovula, do not become richer 

 in infusoria than those which are impnsoned in a single cubic 

 decimetre of air. 



We obtain spontaneous generations by making use of artificial 

 water and air, and even of oxygen, instead of air. 



Wben we mingle together two different fermentiscible liquids, 

 we find, in the mixture, organised beings different from those 

 which the liquids when separate contain. 



In experimenting simultaneously with calcined air, a body 

 heated 200 degrees, and water which has undergone ebullition, 

 we obtain animal and vegetal proto-organisms. Now not one of 

 the reproductory bodies resists boiling water. But the following 

 experiment is assuredly more convincing still. 



A vessel of crystal 0",30 in diameter is washed with sulphuiic 

 acid and filled with distilled boiling water. Then we plimge 

 therein 10 grammes of filaments of flax heated for two hours to 

 150 degrees. We cover it afterwards with a receiver, and we 

 place it in the centre of another large vessel O^jSO in diameter, 

 filled with distilled water. We keep it at a temperature of 28 

 degrees, and at the end of four days the maceration is filled 

 with paramsecia, while we do not find one of these animals, and 

 not even one of their ova, in the large vessel.^ 



But why do the so-called floating germs persist so obstinately 

 in being invisible 1 In effect, atmospheric micrography finds in 

 the air nothing but particles of fecula of wheat or some very small 

 particles of silex. The ovula, the spores are so rare that 

 habitually we do not meet with a single one in a cubic ddcim&tre 

 of air. 



Aerian germs being sc rare can only very slo:wly people Lnf u- 

 1 F.-A. Pouchet, loc. cit., p. 122. 



