172 Dr. Schunck on the Action of 



cess has somewhat advanced, others when it approaches a con- 

 chision — these different effects corresponding to different stages 

 of decomposition in the ferment itself. I think I am correct in 

 saying that there are only two well-known instances of specific 

 effects due to ferments. The one is the decomposition of amyg- 

 daline (and salicine ?) by means of emulsine, the ferment con- 

 tained in almonds ; the other the decomposition of rubian by 

 means of erythrozym. No known ferment, with the exception 

 of emulsine, has any effect whatever on amygdaline*, and none 

 of the usual ferments, such as yeast, decomposing caseine, albu- 

 men, gelatine, or even emulsine, are capable of supplying the 

 place of erythrozym, as far as regards the decomposition of 

 rubian f. These specific effects of emulsine and erythrozym are 

 more characteristic of these bodies than any other property 

 whatever, and serve to distinguish them from one another and 

 from other ferments, with more accuracy than any difference in 

 composition, however great. On the other hand, the decompo- 

 sition of sugar into alcohol and carbonic acid is an effect common 

 to all known ferments. All so-called proteine compounds, such 

 as albumen, caseine, animal membranes, &c., when they enter 

 into decomposition, acquire the properties of ferments. When 

 all other circumstances are alike, the processes of decomposition 

 to which these compounds, when acting as ferments, give rise 

 in other bodies, are precisely the same. The species of decom- 

 position varies only according to the particular stage of decom- 

 position of the ferment itself. During the first stage of decom- 

 position they convert starch into sugar ; during the second gtage 

 they change sugar into alcohol and carbonic acid, bile into 

 cholalic acid, taurine, and other products, and tannic into gallic 

 acid ; when they have entered on the third stage of decomposition, 

 they effect the conversion of sugar into lactic acid, and of lactic 

 acid into butyric acid, carbonic acid and hydrogen. All these 

 various effects may be produced by emulsine, provided the latter 

 be in the state of decomposition appropriate to their respective 

 production. The alcoholic fermentation of sugar is also effected 

 by erythrozym, as I have shown J. 



* I have mixed amygdaline and erythrozym, and amygdaline and mad- 

 der itself, together with water, to the consistence of paste, and allowed the 

 mixtures to stand for days in a warm place, without perceiving any signs of 

 the decomposition of the amygdaline; while a mixture of amygdaline, 

 emulsine, and water will, under the same circumstances, evolve the peculiar 

 smell of oil of bitter almonds in a very short time. 



t Emulsine is indeed not entirely without effect on rubian, but the quan- 

 tity of the latter which it is capable of decomposing, even after a long lapse 

 of time, is extremely insignificant. 



X It is possible that butyric acid may also be one of the products of the 

 action of erythrozym on sugar, though it is not probable, as among these 



