OEGANIC POISONS AND DEUGS 99 



inflammation, not only of the gastro-intestinal tract, but 

 also of the heart, was observed. Such irritation is not 

 typical of cyanide poisoning or that due to Java beans. 

 Animals poisoned by hydrocyanic acid display congestion 

 of the central nervous system and the lungs ; fluid, black, 

 and oily blood ; the cavities of the heart contain bubbles of 

 gas, and all parts of the corpse have a faint smell of bitter 

 almonds. 



Treatment. — The poison should be removed by emetics or 

 the pump, and measures taken to combat prostration — e.g., 

 stimulants and warmth. Atropine has been recommended, 

 and also the injection of sodium sulphide and sodium 

 thioBulphate, in the hope that the comparatively harmless 

 sulphocyanides may be formed. Ammonia and chlorine 

 have been further recommended. According to Claude 

 Bernard, experiments on rabbits show that under ether 

 considerably larger doaes than those ordinarily toxic may 

 be withstood, so that if an animal were kept under anses- 

 thesia it is possible that there might be time for the 

 elimination of the hydrocyanic acid. 



The classical antidote is freshly precipitated ferrous 

 hydrate, which is made by mixing iron sulphate and liquor 

 potasste, and which may be given ad lib. It must not be 

 made with carbonates, for ferrous carbonate does not easily 

 form ferrocyanide, and the production of this harmless 

 salt is the object of the treatment. But the antidote is 

 useless when symptoms have set in, and there is rarely 

 time to apply it in any case. 



Chemical Diagrnosis.— The tests for hydrocyanic acid 

 are excessively delicate. Since hydrocyanic acid is volatile, 

 the separation from tissues is effected by slow distillation 

 in a current of steam of the material, acidified with 

 tartaric acid or dilute sulphuric acid, the hydrocyanic acid 

 being collected in the distillate. 



The best test is the absolutely characteristic formation 

 of Prussian blue by the action of precipitated ferrous 

 hydroxide on a caustic alkali solution of the cyanide ; this 

 leads to the formation of ferrocyanide, and after acidifica- 



