_Mr. Brodie_[304] has also thrown considerable light upon the action of this salt. He observes that the effects of emetic tartar so much resemble those of _arsenic_, which we have already described, and those of _muriate of baryta_, which will form a future subject of inquiry, that it would be needless to enter into a detail of the individual experiments which he made with it. When applied to a wound in animals which are capable of vomiting, it usually, but not constantly, operated very speedily as an emetic; in other respects he found no material difference in the symptoms produced in the different species of animals, which he had been in the habit of employing as subjects of experiment. The symptoms were paralysis, drowsiness, and, at last, complete insensibility; the pulse became feeble, but the heart continued to act after apparent death, and was maintained in action by means of artificial respiration; but never for a longer period than for a few minutes. Whence it would appear, that this poison acts by being absorbed, and that it directs a sedative influence upon the heart, as well as the brain, but that its principal action is on the latter. The length of time which elapses, from the application of the poison to the death of the animal, varies; in some instances _Mr. Brodie_ found that it did not exceed three quarters of an hour, but in others, it was two or three hours, or even longer, before death took place. When a solution of emetic tartar was injected into the stomach of a rabbit, _Mr. Brodie_ observed the same symptoms to take place, as when it was applied to a wound. _Organic lesions discovered by dissection._ _Mr. Brodie_, in his examination of animals poisoned by _emetic tartar_, sometimes found the stomach bearing the marks of inflammation, but at other times, its appearance was perfectly natural. In no case did he discover any traces of inflammation in the intestines. The reader must compare this account with that already given by _M. Majendie_, at p. 282. 1. _Tests for the detection of emetic tartar._ 1. _The poison is in a solid form._ Dissolve a portion of the suspected salt in about fifteen times its weight of boiling distilled water; if it be emetic tartar, the following reagents will identify it, viz. (_a_) _The hydrosulphurets_ will occasion a reddish-yellow precipitate, which is a combination of _oxygen_ and _antimony_, proceeding from the emetic tartar; and of _hydrogen_ and _sulphur_, from the reagent employed. If it be dried on a filter, and mixed with charcoal and the potass of commerce, it gives, by the action of heat, a cake of metallic antimony. (_b_) _Tincture of galls._ This is regarded as the most sensible test of this salt, affording a precipitate of a curdled, dirty white colour, inclining to yellow.