ON CYANOGENESIS IN PLANTS. 
403 
cooling. It is however retained in solution by aqueous solutions of dextrose, a 
peculiarity which accounts for the great difficulty we at first experienced in isolating 
it from the plant. 
It appears to contain water of crystallisation, since it loses weight when heated for 
some time in a water oven, but the amount cannot be accurately determined owing 
to the decomposition which occurs when the substance is heated near 100°. 
Some trouble was met with in obtaining the material in a satisfactory state for 
analysis owing to the difficulty of removing the water of crystallisation without 
causing decomposition. 
The following combustions were made :— 
A. Material recrystallised from alcohol and dried until of constant weight in a 
vacuous desiccator over sulphuric acid. 
•0961 gramme gave '1887 gramme C0 2 C 53 - 6 per cent. 
•0572 „ ILO H 6-5 
•1385 „ „ -2698 „ C0 2 C 53T 
•0885 „ HoO H 7-07 
B. Materia] recrystallised from water and dried at the ordinary atmospheric 
temperature on filter paper. 
•1260 gramme gave ‘2323 gramme C0 2 C 50‘29 per cent. 
•0736 „ H 2 0 H 6-42 
C. Material recrystallised from alcohol and dried in a current of warm air at 80° 
to 90°C. 
'1021 gramme gave ’2051 gramme C0 2 C 54'7 per cent. 
•0452 „ HoO H 4-9 
C 14 H 17 0 7 N.C 2 H 5 0H requires C 53'7 H 6 - 44 per cent. 
C ]4 H 17 0 7 N.HoO „ C 5T1 H 5-8 
C h H 17 0 7 N „ C 54-0 H 5-5 
C 20 H 27 O 12 N „ C 50-74 H 5-7 
The glucoside therefore has the composition represented by the formula 
C 14 H 17 0 7 N, but when crystallised from alcohol or water the crystals which separate 
contain one molecular proportion of these solvents. 
For the glucoside thus isolated from Egyptian Dhurra we propose the name 
dhurrin. 
Hydrolysis of Dhurrin by Acids. Formation of Prussic Acid, Parahydroxybenz- 
cddehyde and Dextrose. 
When an aqueous solution of dhurrin is warmed on the water-bath with dilute 
hydrochloric acid, hydrocyanic acid is almost immediately evolved. If the heating is 
3 F 2 
