176 Scientific Intelligence. 



or of the bisulphuret of tin ; and from the sulphuret of cadmium, to which 

 it bears a greater resemblance, it is distinguished by its ready solubility 

 in a solution of pure potash. On the contrary, the other tests, taken sing- 

 ly, supply no proof whatever of the presence of tartar emetic ; though, 

 when they all agree in their indications, their evidence is not likely to be 

 deceptive. 



In describing sulphuretted hydrogen as a test of tartar emetic, it is al- 

 most unnecessary to state that this gas merely indicates the presence of 

 antimony, without directly showing in what state it existed. But since 

 tartar emetic is the only pharmaceutic preparation of antimony which is 

 soluble in water, the detection of the metal itself, in judicial cases, leaves 

 little doubt of its having been in the form of the double tartrate. This, 

 however, is not a point of much importance, because all soluble antimo- 

 nials are poisonous. 



In order to ascertain if sulphuretted hydrogen may be relied on for dis- 

 covering the presence of antimony in complex animal and vegetable fluids, 

 tartar emetic, dissolved in water, was mixed with tea, broth, porter, and 

 milk, in such quantity that each solution amounted to four ounces, and 

 contained two grains of the compound. Through these solutions, after 

 being acidulated with tartaric acid, boiled and filtered, a current of sul- 

 phuretted hydrogen gas was transmitted during fifteen or twenty minutes. 

 In the three first liquids an abundant precipitation ensued immediately, 

 and the same took place in the milk after boiling. The precipitate subsid- 

 ed easily from each, and the colour of that from the tea, broth, and milk, 

 was quite characteristic. That procured from the porter was not so satis- 

 factory at first ; but on collecting and drying it upon a filter, the paper 

 presented the distinct orange tint of the precipitated sulphuret of anti- 

 mony. 



In recommending the use of tartaric acid, I may observe that the em- 

 ployment' of this substance should in no case be omitted. According to 

 my observation, all the precipitates occasioned in tartar emetic by reagents, 

 sulphuretted hydrogen excepted, as well as by animal or vegetable fluids, 

 are readily dissolved by tartaric acid. Thus the precipitates occasioned 

 by lime-water, or muriatic acid, disappear instantly on the addition of tar- 

 taric acid ; and the compound of tannin and the oxide of antimony, whe- 

 ther formed by the infusion of gall-nuts, tea, or cinchona bark, may easily 

 be rendered soluble by the same means. If milk is present, muriatic acid 

 should likewise be employed, by which the coagulation of the caseous mat- 

 ter is more completely ejBfected. In order, therefore, to form a rule appli- 

 cable to every case, the following directions may be given : The fluid sup- 

 posed to contain tartar emetic should be mixed with a drachm or two of 

 muriatic and tartaric acids, boiled for a few minutes to separate any sub- 

 stance coagulable by heat, and then allowed to cool, and filtered. The 

 liquid should next be exposed to the action of sulphuretted hydrogen, and 

 boiled to expel the excess of the gas ; after which the sulphuret will sub- 

 side if tartar emetic had been present. 



After procuring the sulphuret of antimony by the process above describ- 



