540 Prof. H. E. Armstrong. Enzyme Action as bearing [Apr. 5, 



group, it might be either directly or in consequence of the displace- 

 ment of H by OH. The different effects produced by different 

 organisms, on this hypothesis, would be the consequence of the 

 hydrolysis affecting different systems. As most, if not all, fermentable 

 compounds are asymmetric and the enzymes are undoubtedly also 

 asymmetric bodies, the direction of attack would depend on the 

 character of the asymmetry of both hydrolyte and hydrolyst ; more- 

 over only compatible hydrolysts, i.e., those compatible with the hydro- 

 lyte, would condition hydrolysis and fermentation." 



I then considered that fermentative changes were "presumably 

 functions of the protoplasm." Buchner's researches, however, would 

 seem to necessitate a non-vitalistic interpretation of the phenomena. 

 He has unquestionably proved that fermentation can take place to 

 some extent outside the living cell, but the effect observed has always 

 been of a very transient character, unlike enzyme action in general ; 

 this is the more remarkable, as the amount of energy liberated during 

 fermentation is by no means inconsiderable ; and also because Buchner's 

 observations would lead us to correlate alcoholic fermentation more 

 closely than we have hitherto done with the ordinary sucroclastic 

 action of enzymes. A system such is pictured of enzyme and hexose 

 might well break down into the ordinary products of fermentation, if 

 energy from outside were in some way initially impressed upon the 

 system, as might well happen if it were a part of the protoplasmic 

 complex. It is conceivable that Buchner may have dealt with systems 

 intermediate in complexity between the enzymes proper and the proto- 

 plasmic complex in which exothermic change is still in progress ; but 

 ephemeral systems only. On the other hand, the presence of proteo- 

 clastic enzymes in the expressed fluid may be a cause of the decay of 

 the fermentative activity. But I venture to think the case is not yet 

 fully proved in Buchner's favour ; and however willing we may be to 

 regard alcoholic and lactic fermentations as enzymic changes, such an 

 explanation appears to be altogether inapplicable, for example, to 

 butyric fermentation or to fat formation : we have no reason at 

 present to suppose that the various kinds of fermentation are brought 

 about in essentially different ways. 



In discussing the changes which attend fermentation, I pointed out, 

 in 1895, that "Such changes are known to occur entirely within the 

 cell and are presumably functions of the protoplasm ; in other words, 

 they probably occur within very complex molecular systems of extreme 

 instability, perhaps under the influence of, in contact with, the very 

 same hydrolyst (enzyme) which is so active, when separated from the 

 cell, in promoting the hydrolysis of cane sugar ; or if not, of substances 

 of a similar nature." This explanation has gained greatly in prob- 

 ability now that it is established that the sucroclastic enzymes are very 

 closely related to the alcoholic ferments. 



