Imperial Drop - For Gravel And Kidney Complaints

Take saltpetre 1 oz.; putting it into an iron mortar, dropping in a live coal with it, which sets it on fire; stir it around until it all melts down into the solid form, blow out the coals and pulverize it; then taka an equal amount of bi-carbonate of potassia, or saleratus, and dissolve both in soft water 2 oz.

Dose: from 20 to 30 drops, morning and evening, in a swallow of tea made from flax seed, or a solution of gum arabic.

Source: Dr Chase's Recipes, or Information for Everybody, A.W. Chase