The chlorides of tin are used in the arts of colour-making and dyeing, and the oxide of tin forms part of the putty-powder used for staining glass and polishing silver plate.
There are two chlorides, the protochloride and bichloride. They both form acicular crystals, which are very soluble. It is needless to notice their tests or chemical history; but in order that the following account of their effects on man and animals may be understood, it is necessary to mention, that they are decomposed by almost all vegetable infusions and animal fluids.
Orfila found, that a solution of six grains of the protochloride injected into the jugular vein of a dog killed it in one minute,—that two grains caused death by tetanus in fifteen minutes,—and that so small a quantity as half a grain caused death in twelve hours, the only symptoms being somnolency and catalepsy or fixedness of position.
To these dreadful effects when introduced into the blood, its effects when swallowed are not nearly proportionate. From eighteen to forty-four grains killed dogs in one, two, or three days, efforts to vomit and great depression being the only symptoms; and after death the stomach was found excessively inflamed, and sometimes ulcerated. Its effects when applied externally are still less violent. Two drachms applied to a wound merely caused violent inflammation and sloughing of the part, and death in twelve days, without any internal symptom during life or appearance after death.[[1166]]
These phenomena, considered along with the violent symptoms excited when the poison is injected into the veins, show that, when swallowed or applied outwardly, it acts only as a local irritant.
Tin is absorbed in the course of its action, and may be detected in the liver, spleen, and urine, by boiling them in water acidulated with hydrochloric acid, evaporating the decoction to dryness, charring the residue by means of nitric acid as directed for copper, treating the carbonaceous mass with a mixture of twenty parts of hydrochloric acid and one of nitric acid, evaporating the solution to dryness so as to expel any excess of acid, dissolving what is left in hydrochloric acid diluted with twice its volume of water, and then transmitting hydrosulphuric acid gas. If the precipitated sulphuret of tin has not a fine yellow colour, it must be heated with a little strong nitric acid; after which, if the residuum be again dissolved in diluted hydrochloric acid, a characteristic yellow bisulphuret will be thrown down by hydrosulphuric acid gas. This process may be applied to all organic mixtures containing tin.[[1167]]
The oxide of tin, according to Schubarth, is quite inactive; for he gave an entire drachm to a dog without being able to observe any effect from it whatever.[[1168]] This is what would be expected from its extreme insolubility. Yet Orfila has stated in the early editions of his Toxicology, and repeats in that of 1843, but without noticing the contradictory observations of Schubarth, that one or two drachms of the oxide occasion in dogs all the phenomena of irritant poisoning, and prove invariably fatal.[[1169]]
The metal has been proved by Bayen and Charlard to be inactive.[[1170]] It has been given expressly to dogs without any effect being observed; and it is given in large doses to man for worms, without detriment. No importance therefore can be attached to some alleged cases of poisoning with this metal.[[1171]]
Cases of poisoning with the preparations of tin are rare. Orfila briefly notices a set of cases which occurred to M. Guersent. Several persons in a family took the protochloride, in consequence of the cook having mistaken a packet of it for salt and dressed their dinner with it. They had all colic, some of them diarrhœa; none vomited; and all recovered in a few days.[[1172]] A case is related in the Medical Times of death apparently caused by so small a quantity as half a tea-spoonful of a solution of protochloride. The effects were vomiting, acute pain in the stomach, anxiety, restlessness, thirst, and a frequent, hard, small pulse. These symptoms increased next day; and on the third day death took place, preceded by delirium.[[1173]] As this was a case of suicide, it is probable that some other poison, or a larger dose of the chloride of tin was taken.
Little need be said of the morbid appearances. Besides the signs of violent irritation caused by the poisons of tin in common with other irritants, Orfila always found in dogs a peculiar tanned appearance of the villous coat of the stomach. In the case from the Medical Times the gullet was red, the stomach inflamed externally, and internally thickened, vascular, and pulpy.