
1905.] On the Probable Existence of Emulsin in Yeast. 571 
The washed yeast so prepared had, moreover, lost none of its activity, and the 
following experiments, showing the rate at which washed yeast decomposes 
amygdalin, may be quoted as illustrative of this. For each experiment 
2 grammes of amygdalin were dissolved in 50 c.c. of water contained in a 
small flask, and about 5 grammes of washed yeast were added to the solution. 
A number of flasks were prepared and kept at 40° in a water bath. At 
intervals a flask was taken out and the hydrocyanic acid formed estimated. 
The odour of benzaldehyde was first observed after the flasks had been kept 
at 40° for 74 hours. 
Time after Amount haecedans 
commencement of of hydrocyanic di seas 
. . ecomposed. 
action. acid formed. 
hours. gramme. | Per cent. 
2 | 0 006 | 5°5 
24 0-012 10°5 
48 0 °016 14:0 
72 | 0-019 16 ‘0 
120 | 0 -038 31 °8 
168 | 0 052 42 -0 
| 240 | 0 ‘085 70°8 
| 

The last observation probably represents the limit of decomposition, since 
another flask examined 48 hours later gave practically the same result. It will 
be observed that this limit is a little higher than that (67-8 per cent.) obtained 
with the unwashed yeast. A number of similar experiments were also made 
with the “ Zymin ” or “ Acetondauerhefe,” described by Albert, Buchner, and 
Rapp,* which is prepared by digesting brewers’ yeast with acetone until the cell 
walls are ruptured and the contents egested. This material was also found 
to decompose amygdalin, though much less rapidly than pressed yeast. 
Thus, in one experiment 2 grammes of “ Zymin” were added to an aqueous 
solution of 1 gramme of amygdalin and the mixture kept at about 40°; the 
odour of benzaldehyde was first observed after 74 hours, and at the end of 
90 hours the hydrocyanic acid formed was estimated. This amounted to 
00057 gramme, corresponding to 87 per cent. of the glucoside. A second 
experiment gave 00059 gramme of acid, equivalent to 9°8 per cent. of 
amygdalin, after 114 hours. 
Experiments with Yeast Juice. 
The action of yeast juice (Buchner’s zymase)f on amygdalin was also 
investigated. For a liberal supply of this material prepared from fresh 
* © Berichte,’ 1902, vol. 35. p. 2376. 
t Lbid., 1897, vol. 30, p. 117. 
