Means of detecting Arsenic in the Animal Bodp, S^c. 281 



if not the sulphate of iron from which it was made. Again, he 

 should lay but little stress upon the examination of the intestinal 

 liquid, but direct his attention particularly to the organs. This, 

 together with circumstances peculiar to each case, will explain 

 away any doubt that might arise. 



It ought to be perfectly understood, that the fact of the per- 

 oxide of iron containing a small quantity of arsenic, should be 

 considered rather as a light to guide the chemist in his resear- 

 ches, than as a stumbling-block that might cause him to fall into 

 error. 



Does arsenic exist normally in the afiimal tissues ? 



This perhaps has been one of the most interesting questions 

 ever proposed to chemists, and the investigations that it has 

 given rise to, serve to show the almost perfection of their science, 

 for were it supposed that the whole animal frame contained but 

 one fiftieth of a grain of arsenic, the chemist would not despair 

 not only of being able to detect it, but also of fixing its locality. 



As it regards the bones, it has been clearly demonstrated that 

 they contain arsenic in a minute quantity, but sufficient to place 

 the fact beyond the smallest doubt. 



Whether it exists in the muscles or not, is a question by no 

 means settled. It is true, that with the aid of Marsh's apparatus 

 there can be obtained from muscles digested a long while in nitric 

 acid, taches which are of different shades, such as brilliant white, 

 brilliant yellow, and rusty color; they are volatile and not 

 soluble in nitric acid. Many have supposed their composition 

 to be sulphur with an infinitely small quantity of arsenic. I 

 think that these taches can be more easily accounted for by sul- 

 phur and phosphorus, both of which exist in the muscles, and I 

 am sorry that there is neither time nor opportunity to examine 

 into the truth of this supposition. Nevertheless, whether they 

 contain arsenic or not, the taches obtained have but one charac- 

 teristic belonging to that of arsenic, volatility. 



The next part of this question is very important ; it is whether 

 the organs, such as the liver, spleen, heart, &c., contain normal 

 arsenic. The reason of its importance is, that it is upoi] them 

 that we should place considerable reliance, in the examination of 

 the body of a person supposed to have been poisoned by arsenic. 

 To this we answer, that not the smallest trace has been detected 

 in any of them ; and the answer is based, not upon the few ex- 



