This stuff was evidently used a lot about 125 years ago or so. I have no idea what it was for.
Mrs Beeton’s Book of Household Management – www.mrsbeeton.com
2587. The Common Black Draught.—Infusion of senna 10 drachms; Epsom salts 10 drachms; tincture of senna, compound tincture of cardamums, compound spirit of lavender, of each 1 drachm. Families who make black draught in quantity, and wish to preserve it for some time without spoiling, should add about 2 drachms of spirits of hartshorn to each pint of the strained mixture, the use of this drug being to prevent its becoming mouldy or decomposed. A simpler and equally efficacious form of black draught is made by infusing 1/2 oz. of Alexandrian senna, 3 oz. of Epsom salts, and 2 drachms of bruised ginger and coriander-seeds, for several hours in a pint of boiling water, straining the liquor, and adding either 2 drachms of sal-volatile or spirits of hartshorn to the whole, and giving 3 tablespoonfuls for a dose to an adult.
white pebble 