338 Simple method for the 



bules, will immediately be formed in the cooler part of the 

 tube. 



I have founds that by this process the — th of a grain of cor- 

 rosive sublimate in thirty minims of water, gave a white me- 

 tallic coating to copper turnings, and from them a ring of 

 metallic mercury was sublimed, which, by a common pocket 

 lens, was clearly seen to consist of globules. 



Certain of the precautions necessary to be attended to 

 in the application of the usual methods for detecting the pre- 

 sence of soluble salts of mercury in mixed liquids are also to 

 be borne in mind in conducting this process. Thus, it is 

 well known, that corrosive sublimate undergoes such changes 

 in contact with organic matters as materially to alter the 

 action of its ordinary tests. The researches of Orfila and M. 

 Boullay have shown, that various vegetable and most animal 

 fluids, extracts, fixed and volatile oils, and resins are capable 

 of decomposing corrosive sublimate.* 



Taddei, of Florence, has moreover shown the eminent de- 

 gree in which this power is possessed by gluten, f and on the 

 same property depends the well known antidotal powers 

 of albumen and milk : and Christison has proved, that those 

 changes may occur either at once, after a few hours, or not 

 for some days. J 



Hence in the foregoing process it may occur, that these 

 changes taking place before the substances are submitted 

 to examination, the corrosive sublimate may be removed from 

 the solution, and the insoluble mercurial compound, formed 

 with the organic matters, be thus left upon the calico strainer, 



* Annales de Chemie xliv. 176. According to M. Boullay, a part of the 

 chlorine is disengaged in the form of hydrochloric acid ; and the salt is con- 

 sequently converted into calomel, which is deposited in a state of mixture 

 or combination with vegetable matter. — Orfila Toxicol. Gen. i. 243. 



t Taddei Recherches Sur un nouvel-antidote contre les sublime corrosif. 



X Christison on Poisons, 4th Edit. p. 381. 





