Detection of Aisenic. 5^1 



the trouble of preparation may be saved by those who can pro- 

 cure the chloride of lime, as prepared by our chemical manufac- 

 turers, particularly by Mr Tennant of Glasgow, who has suc- 

 ceeded in saturating the lime completely, so as to form a true 

 bi-chloride, 



5. On the Detection of Arsenic. 



In the number of the Edinburgh Philosophical Journal, 

 vol. xi. p. 389, we gave an account of a paper by Dr Christison 

 of this University, showing the insufficiency of the existing 

 processes for detecting small quantities of arsenic in mixed ani- 

 mal and vegetable fluids, and pointing out a new method, by 

 which so small a quantity as a quarter of a grain might be pro- 

 cured in its metallic state from the most complex mixtures. 

 The second volume of the Medico- Chirurgical Transactions of 

 Edinburgh, published a few months ago, contains another paper 

 by the same gentleman on the chemical and symptomatological 

 evidence of poisoning with arsenic ; and from this it appears 

 that he has applied the proposed process to two medico-legal 

 cases, one of suicide, the other of murder ; that he was success- 

 ful in both instances ; and that the process is one even of much 

 greater delicacy than was alleged in his original paper on the 

 subject. In one case, a portion of the contents of the stomach, 

 in which the first inspectors had failed to detect the poison, was 

 transmitted by order of the authorities from a distant part of 

 the country, and arsenic was discovered to the amount of a twen- 

 tieth part of a grain. In the other case, which Dr Christison him- 

 self examined soon after interment, about ajifteenth part of a grain 

 was detected in the contents and texture together of the stomach. 



For detecting the precise nature of the metallic crust, when 

 its quantity is too minute for its physical characters to be un- 

 equivocally ascertained, the author has added a very elegant 

 test, which was suggested to him by Dr Turner, lecturer on 

 chemistry here. It consists in chasing the crust up and down 

 the tube by heat till it is all oxidated ; when it assumes the ap- 

 pearance of sparkling' crystals^ which may he ascertained^ by a 

 microscope of Jour power s^ to be octaedres. His process now con- 

 sists, therefore, in presenting the same portion of the poison 



JULY — OCTOBER 1826. X 



