an Impurity of Metallic Zz rs 387 
mation upon this point to the pharmacist, and to the chemist who has to’ 
0 with poisoning cases. Our observations, in connection with the facts 
long since established regarding the contamination of foreign sulphuric 
and chlorhydric acids with arsenic, may well lead the pharmacist and the 
analytical chemist to distrust his acids, till accurate experiments have 
proved them to be above suspicion ; and we believe that careful investi- 
gations will hereafter show that arsenic is introduced into pharmaceutical 
preparations by the acids employed in their manufacture to an extent far 
greater than would now be credited. The task of the chemist who is 
pon a qua 
tity of normal animal matter equal to the weight of the suspected sub- 
stances. In this way only can the chemist avoid the fatal uncertainty 
@ return to the examination of other zincs for arsenic. With the 
Same purified acid used in our previous experiments on Pennsylvanian 
and Vieille Montagne zines, we tested 200 grammes of Silesian zine, care- 
fully granulated, and perfectly clean. For half an hour, the hyd 
h 
zine was not perfeetly free from arsenic, and secondly, that it is dangerous 
i i i eaction 
- Briand et Chaudé, et Gaultier de Claubry, Manuel complet de Médecine Légale, 
5me édition, (Paris, 1852,) p. 752. ; ; 
t ©. P. Galtier, Traité de Toxicologie, (Paris 1855,) Tom. i, p. 362. 
