14 THE BEGINNINGS OF LIFE. 



from subsequent contact with everything that could act 

 as a ferment, fermentation would not take place. 



But now, even this cannot be truly affirmed to be 

 a general rule. Some infusions still preserve a first 

 degree of ferment ability even after boiling, whilst others 

 are reduced by this process to the second degree of 

 fermentability. The latter, unlike the former, are un- 

 able to initiate changes by virtue of their own inherent 

 instability : molecular re-arrangements require to be set 

 on foot in them by contact with an unstable substance 

 (dead or living) which is itself undergoing change x . 



That such is the correct explanation of the reason 

 why some fluids do not ferment in bent-neck flasks, 

 seems obvious from the discordant results obtained in 

 many other experiments, after the free admission of 

 uncalcined air to the fluids which had been boiled. 

 The fluids were deprived of their virtues in some cases 



1 In the face of these rival doctrines of fermentation and the similarly 

 unsettled state of our knowledge concerning all the modes of origin of 

 Bacteria, it may now be seen how rash and unscientific was the assump- 

 tion at once indulged in by M. Pasteur and his followers (who are con- 

 stantly trumpeting the logical acumen of their chief), that because the 

 contact of atmospheric particles with the fermentable fluids could be 

 shown to be the cause of their fermentation, therefore living germs 

 must have existed amongst these atmospheric particles. As I have 

 previously pointed out, such a conclusion could only be rendered valid 

 on the strength of the postulate that ' all life proceeds from pre-existing 

 life,' that is to say, on the strength of a postulate which settled before- 

 hand the problem which their investigations were destined to solve. 

 Many of the remarks of Dr. Burdon Sanderson (loc. cit.) concerning the 

 cause of the zymotic qualities of water seem to me to be open to the 

 same criticism. 



