84 



DE. BASTIAN ON THE 



with or without the favouring influence of other altered conditions, 

 give rise to an independent zymotic process. And during the 

 process t5us initiated, a matter (contagium) appears and increases 

 in certain of the fluids or tissues of the body, which is capable of 

 spreading a similar disease far and wide amongst receptive mem- 

 bers of the community. 



Can the germless liquor potassse plus the favouring conditions 

 (the principal of which is a certain high temperature) be regarded 

 as the " cause ' ' of the fermentation ? The answer does not admit of 

 doubt : the eff'ect in question would not have taken place without 

 their influence. The old logical formula in regard to the word, 

 cessante causd cessat et effectus, completely justifies this point of 

 view ; and so also does the definition of Sir John Herschel. A 

 " cause," said this philosopher, is "an assemblage of phenomena 

 which occurring, some other phenomenon invariably commences or 

 has its origin." 



But there is a point of view which must not be lost sight of. 

 It is of considerable importance, and has of late been dwelt upon 

 by Gr. H. Lewes with his usual force and clearness. He says* : — 

 " The fact that it is a convenience to select some one element out 

 of the group, either for its conspicuousness, its novelty, or its in- 

 terest, and that we call it the cause of the change, throwing all 

 the other elements into the background of conditions^ must not 

 make us overlook the fact that this cause — this selected condition 

 — is only efl'ective in coalescence with the others. Every condi- 

 tion is causal ; the eff'ect is but the sum of the conditions." 



This brings us to the only point of doubt which can possibly 

 exist in regard to the interpretation of my experimentf. It is 

 whether our most prominent causal element, the liquor potassaD, 

 exercises its influence («) partly upon the fluid and partly upon 

 certain otherwise dead or impotent germs still lurking within the 

 vessel, or (6) simply upon the mere chemical constituents of the 

 fluid medium, but in such a way as actually to engender minute par- 

 ticles of living matter which thereafter appear as ferment-organisms. 



If a practically dead germ can by any treatment be revived, it 

 may take its place as one of the causal conditions leading to fer- 

 mentation ; hence it is that a certain reserve may still be main- 

 tained as regards the absolute proof of the possibility of a germ- 

 less origin of common fermentations, and the almost simultaneous 

 occurrence of a new birth of living units (Archebiosis). 



* ' Problems of Life and Mind,' vol. ii. p. 390. t See p. 47. 



