ARSENIC. 181 



443. POISONOUS PROPERTIES OF ARSENIC. 



What is said 



of arsenic as White arsenic or arsenious acid is a fearful 

 a poison? poison, and more frequently employed than 

 any other substance, for the destruction of life. But 

 its detection, and the entire demonstration of its pres- 

 ence in the body, after death, or in materials which 

 have previously been ejected from the stomach, is cer- 

 tain. 



444. No one but a professional chemist 



What is said 



of its detec- should undertake such an investigation, 

 tijon ? involving, as it does, the issues of life and 



death. No one else, indeed, can, be qualified to guard, 

 with certainty, against the presence of arsenic in the 

 chemicals which are used in the process, or in other res- 

 pects, to bring the inquiry to that point of absolute de- 

 monstration, which is always required in judicial inves- 

 tigations. But the methods of detection, being simple, 

 and a subject of interesting and instructive experiment 

 to the student, will be briefly described in the paragraphs 

 which follow. Many other compounds of arsenic, be- 

 side arsenious acid, are highly poisonous. 



How arsenic i* ^45. DETECTION OF ARSENIC. If a few 



detected? drops of a solution of chloride of arsenic* 



be added to the liquid from which hydrogen is being 

 evolved from a vial, by the ordinary process, the 

 nascent hydrogen decomposes the chloride of arsenic 

 and carries off the metal, in the form of a gas. On sub- 

 sequently kindling the hydrogen jet, and bringing 



* Such a solution is prepared, by dissolving white arsenic in hydro- 

 chloric acid. 



