398 Miscellaneous Intelligence. 



which copper is used, and which will detect the -soJoTr ^^ 

 the hydrocyanic acid in solution in water. The mode of opera- 

 tion is to render the liquid containing the hydrocyanic acid, 

 slightly alkaline with potash ; add a few drops of sulphate of 

 copper, and afterwards sufficient muriatic acid to re-dissolve the 

 excess of oxide of copper. The liquid appears more or less milky, 

 according to the quantity of hydrocyanic acid present. A sin- 

 gular property of the precipitate thus diffused through 20,000 

 parts of water, is, that after some hours it re-dissolves, especially if 

 the muriatic acid added be in sensible excess. 



Nitrate of silver is also a good re-agent for detecting hydro- 

 cyanic acid, but the appearance too much resembles that produced 

 by the presence of muriatic acid. 



A cat was poisoned by twelve drops of the hydrocyanic acid 

 in sixty drops of water ; the animal died one minute after 

 having swallowed the poison. At the moment of its death a 

 vapour came from its throat smelling strongly of the acid, and a 

 paper moistened with alkali when held to it was afterwards ren- 

 dered blue by persulphate of iron. The animal was retained at 

 the temperature of 50° F. for eighteen hours, and then opened. 

 The odour of prussic acid was readily perceived in the brain, spinal 

 marrow, and thoracic organs. It was but slightly sensible in the 

 stomach, which contained nothing but mucus ; but on cutting the 

 organ in pieces it was developed. The stomach was cut into pieces 

 under water, and distilled with the water ; when about an eighth of 

 the liquid had passed over, it was mixed with potash and per sul- 

 phate of iron, and soon gave a feeble blue tint, leaving no doubt 

 of the presence of hydrocyanic acid. The test by copper gave it 

 still more sensibly. The copper tested^ prussic acid also in the 

 intestines, but the persulphate of iron did not. 



The experiments repeated on a young cat with one drop of the 

 acid gave the same results. 



A dog being poisoned by twelve drops of the acid died in half 

 an hour. The body was opened fifty-three hours after death, and 

 both the contents of the stomach, and the stomach itself, distilled 

 as before, gave by sulphate of copper decided proofs of the pre- 

 sence of the prussic acid. 



Four drops diluted with water were injected into the rectum of 

 a young cat ; forty-eight hours after death the intestine was 

 extracted and examined, and gave evidence of the presence of the 

 poison. 



M. Lassaigne observes that, when the quantity of hydrocyanic 

 acid is very small, its presence is not shewn by the sulphate of 

 iron, until twelve or even eighteen hours after its addition, whilst 

 the sulphate of copper discovers it immediately; and that the effect 

 of the latter had frequently disappeared before the first had be- 

 come evident. The experiments indicate, 1. That, from a ten 

 thousandth to a twenty thousandth of hydrocyanic acid may be 



