406 
PROFESSOR WYNDHAM R. DUNSTAN AND DR. THOMAS A. HENRY 
collected in alkali and titrated. The sugar in the residue was estimated gravi- 
metrically by reduction of Fehling’s solution. 
T56 gramme gave a distillate requiring 2‘58 cub. centims. — silver nitrate 
= 8'9 per cent. HCN. 
T702 gramme cuprous oxide = '085 gramme dextrose = 54’5 per cent. 
C 14 H 17 0 7 N requires 8'6 per cent. HCN and 57T per cent, dextrose. 
C 20 H 27 O 13 N „ 6-01 „ HCN and 80T 
The formula C u H 17 0 7 N for dhurrin is therefore confirmed, and the hydrolysis 
of dhurrin by emulsin, or by dilute acid, may be expressed by the equation 
C u H 17 0 7 N + H 3 0 = C 7 H g 0 2 + C 6 H 12 0 6 + HCN. 
Alkaline Hydrolysis of Dhurrin, Dhurrinic Acid. —When the glucoside is warmed 
with aqueous alkalis, it dissolves, with the evolution ot ammonia, but no dextrose is 
formed. On evaporation the solution leaves a sticky hygroscopic residue which 
cannot be induced to crystallise. 
When the hydrolysis is carried out in alcoholic solution by adding a solution of 
sodium in absolute alcohol to a similar solution of the glucoside, a precipitate forms 
after a few minutes, consisting of the sodium salt of the acid corresponding to dhurrin, 
which is its nitrile. This acid may therefore be called dhurrinic acid. The sodium 
salt is highly hygroscopic, it absorbs moisture and becomes gummy when removed 
from the dry alcohol, and is therefore difficult to free completely from the accom¬ 
panying sodium carbonate. The free acid is almost more intractable than the sodium 
salt, and, so far, has only been obtained as a syrup containing sodium chloride. 
Recourse was therefore had to an examination of its decomposition products in order 
to establish its constitution. 
Hydrolysis of Dhurrinic Acid. —A quantity of the crude sodium salt, prepared as 
above described, was dissolved in water and dilute hydrochloric acid added. The 
mixture was heated on the water-bath for an hour, and when cold extracted several 
times with ether. The ethereal solution was dried and the solvent removed by 
distillation, leaving a brown oil, which after several days deposited minute trans¬ 
parent needles. These were dried by absorption of the viscous mother liquid in a 
porous tile. 
The substance thus obtained is at first colourless, but in a few days becomes 
slightly brown. It is soluble in boiling water, alcohol, and ether, and after recrystal¬ 
lisation melts at 180°. With ferric chloride in aqueous solution it gives a slight 
brown coloration, and with bromine water a precipitate, which after recrystallisation 
from alcohol melts at 185°. 
The acid liquid after extraction with ether strongly reduces Fehlixg’s solution, 
and therefore probably contains dextrose. 
The yield of the crystalline hydrolytic product furnished by the hydrolysis of 
