A percolator, with alternate layers of broken glass, which have been well washed, first with hydrochloric acid and plentifully rinsed with distilled water, is the first requisite. This is charged with pieces of crude licorice juice, from the size of a hazel nut to that of a walnut, which are weighted down with well-washed pebbles. The percolate is kept for 3 days in well corked flasks which have been rinsed out with alcohol beforehand. Decant and filter and evaporate down rapidly, under constant stirring, or in vacuo. The extract should be kept in vessels first washed with alcohol and closed with parchment paper, in a dry place—never in the cellar.

To dissolve this extract, use water, first boiled for 15 minutes. The solution should be kept in small flasks, first rinsed with alcohol and well corked. If to be kept for a long time, the flasks should be subjected for 3 consecutive days, a half hour each day, to a stream of steam, and the corks paraffined.

There is frequently met with in commerce a purified juice that remains clear in the mixtura solvens. It is usually obtained by supersaturation with pure ammonia, allowing to stand for 3 days, decanting, filtering the decanted liquor, and quick evaporation. Since solutions with water alone rapidly spoil, it is well to observe with them the precautions common for narcotic extracts.

fermented. The bark is then pulverized, boiled, and washed. Artificial bird lime is prepared by boiling and then igniting linseed oil, or boiling printing varnish until it is very tough and sticky. It is also prepared by dissolving cabinetmakers' glue in water and adding a concentrated solution of chloride of zinc. The mixture is very sticky, does not dry on exposure to the air, and has the advantage that it can be easily washed off the feathers of the birds.