926 
From other experiments it has become evident that benzaldehyde 
when used in very slight concentrations, may serve as nutriment 
for Aspergillus niger. 
From the above results it may also be expected that in amygdalin 
containing liquids to which emulsin has been added Aspergillus niger 
will not develop. 
This follows too from the experiments which are united in 
Table III. 
FABLE il: 
50 cm.3 tapwater, in which dissolved 0,15 % NHyNOs, 0,15 %/o KH,PO,, 
0,1 % 9 magnesiumsulfate (crystallised). Temp. 33°. 
| | Development 
NO. | Dissolved - on 
| After 3 | 5 days 
1, 2, 3 | 2% glucose rather vigor. growth, 
| beginning formation, 
| a Spor vigorous 
4,5 | 2/9 glucose + 0,04 9%) emulsin | vigorous growth, | growth 
6 209 glucose + 0,1 9 emulsin many spores | many spores 
1, 8, 9 | 2% amygdalin "rather vigor. growth, 
rather many spores | 
of the liquid resem- 
bles benzaldehyde 
or (and) HCN. 
just as after 
3 days !) 
10, 11 | 20/, amygdalin + 0,04, emulsin ’ no growth,the smell) 
12 20/, amygdalin + 0,1 % emulsin | 
The emulsin used (Merckx) had no retarding influence on the 
development of Aspergillus niger with glucose as source of carbon. 
The retarding influence of emulsin stated in solutions containing 
amygdalin could therefore only be ascribed to the products of 
hydrolysis of the amygdalin viz benzaldehyde and HCN. 
The above experiments prove that when important quantities of 
amygdalin, before being assimilated, are already dissociated into 
glucose, benzaldehyde and HCN outside the organism Aspergillus niger 
will not develop. It is proved, too, that this is caused especially by 
the retarding action of benzaldehyde. ; 
The strong retarding action of benzaldehyde can on one side be 
explained by its strong solubility in fats (benzaldehyde in every 
proportion is miscible with olive oil) and on the other side by the 
possibility of a rapid conversion into benzoic acid. Benzaldehyde 
') After 30 days Nos. 10, 11 and 12: no growth, but the smell of benzaldehyde 
or (and) HCN can no more be stated. 
