of Arsenic in Cases of Poisoning. S41 



which the precipitation of an arseniated sulphur may take 

 place, because the hydrogen of both in the test-fluids becomes 

 oxidized by means of the air. The muriatic acid obtained by 

 means of such a sulphuric acid contains also arsenic. We must 

 therefore use, in such experiments, distilled sulphuric acid, but 

 not until we have previously tested it by means of sulphuretted 

 hydrogen for arsenic. The same applies to the muriatic acid 

 used in such experiments. In all cases of this kind we cannot 

 use too much caution. 



The reduction- test h the only certain one, and it renders all 

 others superfluous. If this does not succeed, the result is al- 

 ways unsatisfactory. Even the garlick arsenical smell so much 

 depended on, is not to be trusted without actual reduction, as 

 such a smell is sometimes evolved from the animal matter from the 

 stomach. We may conclude by remarking, that no chemist or 

 medical man can conscientiously and legally appear in a public 

 court, as an evidence in such a case, without he has actually 

 himself taken the contents from the stomach, or has had them 

 sent to him, under proper seals, by a trust-worthy medical man, 

 who declares on oath that he has taken the same from the sto^ 

 mach *. 



On a Chemical Composition of ZmJcenite and Jamesonite. By 

 H. Rose, Member of the Royal Academy of Berlin. And 

 Description and Analysis of Pyrochlore^ a new Mineral. 

 By F. WoHLER. 



I. On the Chernical composition ofZinkenite and Jamesonite, 



JL he Zinkenite, in its chemical composition, approaches more 

 nearly to Jamesonite and red silver, than to any other minerals. 

 I found it to contain the following constituent parts : Sulphur 



• From the great delicacy of the reduction-test, it is evident that extremely 

 minute portions of arsenic may be detected. This being the case, the court 

 is entitled to demand of the chemist or medical man, on examination, whether 

 or not he can prove that the articles of food, used by the deceased, did not 

 contain minute portions of arsenic. Bread, for instance, is sometimes adul- 

 terated with alum ; alum is prepared, at times, from aluminous rocks, con- 

 taining iron-pyrites; and iron-pyrites, as mentioned by Berzelius, contains 

 arsenic. This view might be farther illustrated. — Ed. 



t In the third analysis, the quantity of sulphur could not be determined. 



JANUARY — MARCH 18^7. % 



