TRANSACTIONS OF THK SECTIONS. 69 



being more volatile it is found above the crust of metal, and in the 

 oxydizing process forms sulphurous acid and disappears, vi'hile the 

 arsenious acid condenses. 



It sometimes happens that arsenic is contained in substances which 

 prevent the ordinary processes from being followed, for instance in 

 the case of Sophia Edney, who was convicted at Taunton of poisoning 

 her husband. The author found about an eighth of a grain in the 

 duodenum (the contents of the stomach having been thrown away by 

 the surgeon who examined the body, under the belief that an ulcer 

 found in the stomach was sufficient to account for death) ; the only 

 other matters brought for examination were a few grains of bacon-fat 

 scraped from the edges of a frying-pan. In the fat he could find no 

 arsenic, and the potatoe being an amylaceous substance, it was in 

 vain to try the usual reagents or to make a filtered solution. It was 

 therefore projected into melted nitre ; when it was deflagrated, diluted 

 acetic acid was added to rather more than neutralize the carbonate of 

 potass resulting from the deflagration of the charcoal of the vegetable 

 and animal substances. A stream of sulphuretted hydrogen was then 

 passed through it, which turned it yellow, and upon deposition and sub- 

 sequent treatment in the way alluded to before, enough was obtained 

 to take to a jury : specimens of the reduced metal, of arsenious acid, 

 Scheele's green, arsenite of silver and orpiment, although the reduced 

 arsenic was not more than ybo °^ ^ grain. It had been said by the 

 dying man that his wife had fried potatoes in this pan for him and he 

 had not been well since. The pan had been subsequently used to fry 

 bacon, which had been eaten with impunity by two persons, exclusive 

 of the prisoner, who had herself " eaten a bit as big as a nut ;" yet there 

 was enough left adhering to the pan to prove her guilt, which her con- 

 fession subsequently acknowledged. 



Although nitre afi^ords an excellent means of removing all organic 

 matter, and thus leaving the operator free from all embarrassment, yet 

 it cannot be depended on in quantitative analysis, as a certain propor- 

 tion is volatilized during the process ; this loss might be reduced by 

 putting a little nitre in the solution before evaporating to dryness. 



The plan of discovering arsenious acid by arseniuretted hydrogen, 

 and depositing the arsenious crust during its combustion, recently pro- 

 posed by Mr. Marsh of Woolwich, was described by Mr. Herapath as 

 the most elegant that could be conceived, and at the same time the 

 most sensitive ; he suggested the following precautions for the purpose 

 of evidence before a jury. The zinc used for the preparation of hydro- 

 gen should have been treated by the experimenter in the same way 

 without arsenic, or it might be supposed that the arsenic was contained 

 in the zinc ; the metallic crust should be so received as to be kept as 

 much as possible from atmospheric air, otherwise it would lose its lustre 

 by passing into the " Fly Powder " of the Germans. 



Instead of a plate of glass to receive the crust Mr. H. used one of 

 mica, with three drops of water in separate places on one of its sur- 

 faces ; if the flame was allowed to play under one of those drojis, the 

 evaporation of the water kept the place cool, and the crust whs thicker 



