POISONOUS CYANIDES. 
§§ 275 - 277 -] 
223 
should be 17 grms. to the litre ; each c.c. then =*0054 hydrocyanic acid, 
or -01302 grm. of potassic cyanide. 
Essential oil of bitter almonds may also be titrated in this way, 
provided it is diluted with sufficient spirit to prevent turbidity from 
separation of the essential oil. If hydrocyanic acid is determined gravi- 
metrically (which is sometimes convenient, when only a single estimation 
is to be made), it is precipitated as cyanide of silver, the characters of 
which have been already described. 
§ 275. Case of Poisoning by Bitter Almonds. —Instances of poisoning by bitter 
almonds are very rare. The following interesting case is recorded by Maschka :— 
A maid-servant, 31 years of age, after a quarrel with her lover, ate a quantity of 
bitter almonds. In a few minutes she sighed, complained of being unwell and faint; 
she vomited twice, and, after about ten minutes more had elapsed, fell senseless and 
was convulsed. An hour afterwards, a physician found her insensible—the eyes rolled 
upwards, the thumbs clenched within the shut fists, and the breathing rattling, the 
pulse very slow. She died within an hour and a half from the first symptoms. 
The autopsy showed the organs generally healthy, but all, save the liver, exhaling 
a faint smell of bitter almonds. The right side of the heait was full of fluid dark 
blood, the left was empty. Both lungs were rich in blood, which smelt of prussic 
acid. The stomach was not inflamed—it held 250 grms. of a yellow fluid, containing 
white flocks smelling of bitter almond oil. In the most dependent portion of the 
stomach there was a swollen patch of mucous membrane, partially denuded of epi¬ 
thelium. The mucous membrane of the duodenum was also swollen and slightly 
red. The contents of the stomach were acid, and yielded, on distillation, hydride of 
benzole and hydric cyanide. Residues of the almonds themselves were also found, 
and the whole quantity taken by the woman, from various data, was calculated to be 
1200 grains of bitter almonds, equal to 43 grains of amygdalin, or 2-5 grains of pure 
hydric cyanide. 
Poisonous Cyanides other than Hydric and Potassic Cyanides. 
§ 276. The action of both sodic and ammonic cyanides is similar to that of potassic 
cyanide. With regard to ammonic cyanide, there are several experiments by Eulen- 
berg, 1 showing that its vapour is intensely poisonous. 
A weak stream of ammonic cyanide vapour was passed into glass shades, under 
which pigeons were confined. After a minute, symptoms of distress commenced, then 
followed convulsions and speedy death. The post-mortem signs were similar to those 
produced by prussic acid, and this substance was separated from the liver and lungs. 
§ 277. With regard to the double cyanides, all those are poisonous from which hydric 
cyanide can be separated through dilute acids, while those which, like potassic ferro- 
cyanide, do not admit of this decomposition, may often be taken with impunity, and 
are only poisonous under certain conditions. 
Sonnenschein records the death of a colourist after he had taken a dose of potassic 
ferro-cyanide and then one of tartaric acid ; and Volz describes the death of a man 
who took potassic ferro-cyanide and afterwards equal parts of nitric and hydrochloric 
acids. In this latter case, death took place within the hour, with all the symptoms 
of poisoning by hydric cyanide ; so that it is not entirely true, as most text-books 
declare, that ferro-cyanide is in no degree poisonous. Carbon dioxide will decom¬ 
pose potassic ferro-cyanide at 72°-74°, potassium ferri-cyanide being precipitated— 
K 3 Fe(CN) 6 . A similar action takes place if ferro-cyanide is mixed with a solution 
of peptone and casein, and digested at blood-heat 2 (from 37° to 40° C.), so that it is 
believed that when ferro-cyanide is swallowed HCN is liberated, but the quantity 
1 Gewerbe Hygiene, p. 385. 
2 Autenrieth, Arch. Pharm., ccxxxi. 99-109. 
