IV. Stains on the Clothes, &c.
1. The strong acid changes the colour of black woollen cloth to a dirty brown, the edges of the spots assuming a reddish tint after a few days. The dilute acid on the same cloth produces a red stain, which in time becomes brown.
2. The spots made by the strong acid remain damp for some time—strong sulphuric acid, having a great affinity for water, continually absorbs moisture from the atmosphere.
3. The spot should be cut out, boiled in distilled water, or digested with alcohol, filtered and tested for free sulphuric acid.
4. A portion of the cloth not touched by the acid should be tested, in order to show that the sulphuric acid found is not due to sulphates present in the cloth.
5. An acid sulphate—bisulphate of potash—gives a reddish stain to black cloth like that produced by the dilute acid. Test for this salt by incineration.
Fatal Period.—Average time before death ensues is from two to twenty-four hours. The shortest time was one hour, but in children death may be instantaneous. Life, however, may be prolonged for some weeks, or even months.
Fatal Dose.—One drachm in a healthy adult has proved fatal; on the other hand, however, four ounces have been swallowed without being fatal.
Treatment.—As before mentioned.
N.B.—This acid in past years has given rise to several actions, it having been employed to disfigure the person by throwing it in the face.