306 STAHJRE AND flETECTlON OF METALLIC POISONS. 



XL 



On the Nature and Detection of the different Metallic Poisons. 

 In a Letter from Mr. Charles Sylvestek. 

 To WlUiam Nicholson, Esq. 

 DEAR SIR, 

 Nattre and A I^THOUGH an inquiry relative to the nature and detec- 



detection cif J^ ^ jioa of the difteient metaliic poisons would need no apo- 

 the fhlierent , . , ^ . . ,. ,, r 



metallic poi- ^^oY' ^^ ^"7 ps^iod, tor its introduction to the readers ot your 

 sons, a subject Journal, yet I feel it to be the less necessary, at the present 

 o. inquiry. moment, from the great interest which has, of late, been ma- 

 nifested for investigations of this nature ; and am induced, 

 therefore, to send you the following essay, which was, for the 

 most part, prepared for a particular purpose many months ago. 

 Should it tend to lessen any of the difficulties attendant on a 

 subject of such importance, or at all interest those who have 

 devoted themselves to researches of this description, it will 

 fully repay me for the labour of transcribing it. 

 I remain, dear Sir, 



Your's very faithfully, 

 CHARLES SYLVESTER, 

 Derh]/, Nov. idth, 1812. 



/. Arsenic. 



White oxide "^^ ^ poison the most virulent, and, at the same time, the one 

 of arsenic. most to be dreaded, from its extreme insipidity, and the con- 

 sequent readiness with which it may become an instrument in 

 the hands of the murderer, or be received into the system by 

 Detection of accident, is the white oxide of arsenic. For the detection of 

 *^' this substance, when thus admitted, various processes have, at 



Dr. Bostock's different times, been recommended ; and the papers of Dr. 

 Suy p^efS°^' Rostock, published in the 5th vol. of the Edinburgh Medical 

 red. and Surgical Journal, have, very generally, been thought to 



contain the best directions for this purpose. After various ex- 

 periments he decides in favour of sulphate of copper, and 

 carbonate of potash, which precipitate the white arsenic under 

 Objection to the form of Scheete's green. It cannot fail to have occurred, 

 "• however, to every one who has repeated these experiments, that 



the phenomena produced in this process are very much too am- 

 biguous to enable a man, where the life of an individual is at 

 ''" stake. 



