68 Iodide of Potassium, as a Test for Arsenic. 



mountains of snow at the poles, or exposed to a vertical sun in the 

 sultry regions of the torrid zone." 



These little animals may class with the amfphibia, which have cold 

 blood, and are generally capable in a low temperature of a torpid state 

 of existence ; hence, their icy immersion did no violence to their 

 constitution ; and the possibility of their revival, by heat, is well sus- 

 tained by analogy : but their generation, their parentage, and their 

 extraordinary transmigration are to me subjects of profound aston- 

 ishment. 



The dangerous and repulsive notion of " living monades" perva- 

 ding the universe, and constituting integral parts of " all creation," 

 will, perhaps, be more forcibly resisted, by referring to a reasonable 

 cause, those occasional phenomena, than by the ablest arguments, in 

 the abstract, which can be framed to demonstrate the fallacy of tlie 

 doctrine. 



Canibri'.lge, E. 5. Maryland, Jan. 27, iSoO. 



Art. IX. — The Iodide of Potassium, [Hydriodate of Pot ass a of the 

 shops,) as a test for Arsenic, tvith remarks upon the nature and 

 properties of the compound formed ; by 3. P. Emmet, Professor 

 of Chemistry in the University of Virginia. 



Although the detection of arsenic, even in minute quantities, is, 

 at present, a problem of sufficient accuracy, the most perfect of the 

 operations recommended for this purpose often require too m.uch 

 manipulation for inexperienced persons. On this account, as well as 

 with the view of extending our means of research, it must always be 

 desirable to increase the list of reagents even of a secondary charac- 

 ter. It is not pretended to assign to the process, about to be de- 

 scribed, a more elevated position, in as much as it fails to exhibit the 

 mineral poison in such minute quantities as can be effected by means 

 of sulphuretted hydrogen, ammonio-nitrate of silver, he. It has, 

 however, peculiar advantages arising from the great facility of its ap- 

 plication, and may always be employed with benefit in connexion 

 with those agents that indicate more minute quantities. 



The solution to be tested may contain either arsenious acid alone 

 or combined with an alkali, as is recommended for other tests. Even 

 uncombined iodine may be substituted for the hydriodate, in cases 

 where the arsenic has been previously made to combine with an al- 



