Italian or Spanish juice may be purified by the following method: - Take a sugar-mould, close the vent-hole with a stopper, place inside it some coarse tow, and over this some clean straw, laid crossways in layers of an inch each, then the sticks of liquorice placed upright, and packed closely in the mould with chopped straw cut rather long. When this arrangement is completed to within an inch of the brim, pour water over the liquorice, allow it to remain for 24 hours, then draw it off, and add more. The liquor, on evaporation, yields an extract perfectly soluble in water. Litmus. A preparation of some kind of lichen, probably Lecanora tartarea, or Roccella tinctorea, or both. It is prepared by a process similar to that used for Archil; but it is moistened by a mixture of Carbonates of Ammonia and potash, or soda, the addition of the carbonates of ammonia, or of potash or soda, being essential to the development of the blue colour. It is made up with chalk or plaster of Paris into small cakes for the market. See Tests.