THE BEGINNINGS OF LIFE. 235 



Experience has shown me that if an infusion has 

 been heated for a time to 2I2F, the pellicle which 

 forms on its surface very frequently never gives rise to 

 embryonal areas; if the infusion has been prepared 

 at a temperature of 149- 158^ the embryonal areas 

 which form will give origin to Fungus-germs ; whilst in 

 a similar infusion prepared at i2o-i3OF, the embry- 

 onal areas, which seem at first to be in all respects 

 similar, break up into actively-moving Monads. It 

 remains for us to see what changes may take place in 

 a pellicle which forms on an infusion or maceration 

 prepared with cold water (6o-7oF). 



Before passing to a description of these phenomena, 

 however, I will describe the mode of origin of the 

 embryos of some organism whose real nature is un- 

 known the final stages of its development not having 

 been traced. As far as they were seen, the stages were 

 of a very positive character. 



I have observed these early stages in two different 

 infusions; but in each case, after a certain stage of 

 development had been achieved, no further progress 

 seemed to be made for about two days, and then the 

 pellicle unfortunately broke up and sank to the bottom. 

 The arrest of development may therefore have been 



that embryonal areas yielding Fungus -germs do not appear in infusions 

 prepared at 2i2F, because such heat is destructive to them; when at 

 the same time he vehemently contends, in answer to other experiments, 

 that similar Fungus-germs are not hindered from developing after expo- 

 sure to such a temperature, or to others which are much higher. 



