We are not aware that there is any modern case of poisoning by this salt[[320]]. The medical practitioner, however, ought to know, that common salt, is its true antidote; indeed so completely does it decompose and separate it from water, that if a saturated solution of nitrate of silver be filtered through common salt, it may be afterwards drunk with impunity. M. Orfila, by a series of experiments, has shewn that if the muriate of soda be administered a very short time after the ingestion of lunar caustic, it will disarm it of its virulence by transforming it into an insoluble muriate, possessing no power of acting on the animal œconomy.
Chemical processes for the detection of Lunar Caustic.
If a small portion of the salt can be procured it may be dissolved in distilled water, and immediately identified by the following tests.
a. Muriatic acid, or any soluble Muriate, will precipitate the muriate of silver, which is white, curdled, very heavy, insoluble in water, or nitric acid; but soluble in liquor ammoniæ; when exposed to the air it acquires a black colour.
b. Potass, Soda, and Lime water, will occasion a precipitate of the oxide, of a deep brown colour.
c. Ammonia. This alkali will form an ammoniuret of silver, and in consequence of the solubility of this new product, little or no disturbance is occasioned by the test.
d. Arsenite of Potass. As all re-agents must be considered as reciprocal in their operation, it is hardly necessary to state that this is one of the best tests for nitrate of silver. See the history of its effects at p. [240].
If it should be necessary to discover the nitrate of silver amongst the fluids vomited, or those contained in the stomach of the deceased, we are very properly directed by M. Orfila to filter, and then assay by the appropriate tests; if, however, the different aliments should disguise the characteristic colour and appearance of these precipitates, we must proceed to desiccate and calcine them in order to obtain the silver in a metallic state.
The Concentrated Acids.
These must be regarded as the most terrible of all corrosive poisons. Their action is so immediate and energetic, as generally to destroy the membranes of the stomach, before their peculiar antidotes can be applied. Notwithstanding the obvious suffering they must occasion, and the facility with which they may be detected, such bodies have frequently, especially in France, been the instruments of suicide and murder; whilst in this country, we have had many lamentable illustrations of their deadly force, by their ingestion from fatal carelessness. In conformity with our general plan we shall proceed to consider the individual substances included under this general class, although the symptoms do not materially differ in the different kinds, nor are the indications of cure peculiar to any of them. There are however chemical characters which exclusively belong to each acid, with which the forensic physician must be accurately acquainted, in order that he may be enabled to detect their presence.