574 Mr. A. Gordon Salamon [March 29, 



organised structure, and its power of effecting the degradation of 

 carbohydrates into alcohol and carbonic acid gas is but one of the 

 features connected with its life-history. Moreover, it is one which is 

 typical of a whole group of fungi. 



The soluble ferments, on the other hand, are unable to effect this 

 radical decomposition, but are endowed with the property of hydro- 

 lising, and thereby producing a constitutional modification or partial 

 degradation of some carbohydrates and other substances of complex 

 composition. They are probably typified by certain molecular group- 

 ings common to them as a class, but they are not organised, and have 

 indeed nothing beyond what I have stated in common with fungi. It 

 is true that certain of these soluble ferments are contained in fungi 

 which themselves are capable of producing alcoholic fermentation, 

 such, for instance, as the invertase in yeast ; but they are not 

 contained in all alcohol-producing fungi. Their function, when 

 present, would seem to be that of a reserve material, capable, when 

 necessary, of effecting the preparation of a saproj^hytic food by alter- 

 ative action, so as to adapt it for subsequent radical attack by the 

 fungus. In this connection it must not be forgotten that suli^huric 

 acid, hydrochloric acid, and indeed most mineral and organic acids, 

 can produce the same alterative action ujDon these carbohydrates, and 

 are employed in very large manufacturing operations for the purpose. 

 It would therefore seem quite reasonable to include these niincral 

 acids among the so-called soluble ferments, if the latter are entitled 

 to rank as a distinct class. 



Alcoholic fermentation, although caused by the action of yeast, 

 which is a fungus, is by no means peculiar to one j^articular species 

 or geuus of fungi. Indeed, the list of those organisms which, under 

 certain conditions, will excite alcoholic fermentation, is continually 

 being augmented. But the life conditions are now tolerably well 

 understood. The fungal food must be present in a state of solution ; 

 the supply of free oxygen must be extremely restricted ; the tem- 

 perature must be maintained wdthin certain limits for each particular 

 species or variety ; there must be present an adequate but not too 

 great a supply of carbohydrate, preferably a sugar, in solution ; and 

 the fungus must, when immersed in the fluid, be capable of growth 

 and reproduction. 



With regard to the carbohydrate food, some points of very great 

 interest are noticeable. All carbohydrates are not equally suitable, 

 though in most cases the fungus contains within itself the chemical 

 components that may, when required, adapt it to assimilation. Ordi- 

 nary yeast, for instance, cannot ferment cane sugar ; it has, first of 

 all, to be transformed, by the invertase contained in yeast, or by 

 other known means, into what is known as invert sugar. This con- 

 sists of two glucoses present in equal quantity — the one dextrose, 

 capable, as its name implies, of turning the ray of polarised light to 

 the right; the other, laevulose, capable of rotating it to a definite 

 extent to the left. Both these glucoses have the same composition ; 



