or Lac, in natural history, improperly called gum lac, a sort of wax of a red colour, collected in the East Indies by certain insects, and deposited on sticks fastened for that purpose in the earth. It is brought over, either adhering to the sticks, or in small transparent grains, or in semi-transparent flat cakes: the first is called stick lac, the second seed lac, and the third shell lac. On breaking a piece of stick lac, it appears composed of regular cells like the honey-comb, with small corpules of a deep red colour lodged in them: these are the young insects, and to these the lac owes its tincture, for when freed from them its colour is very dilute. The shell and seed lacs, which do not exhibit any insects or cellular appearance upon breaking, are supposed to be artificial preparations of the other: the seed sort is said to be the stick lac bruised and robbed of its more soluble parts; and the shell to be the seed lac, melted and formed into cakes. The stick lac therefore is the genuine sort, and ought alone to be employed for medicinal purposes. This concrete is of great esteem in Germany and other countries, for laxity and spongeiness of the gums, proceeding from cold, or a scorbutic habit: for this use the lac is boiled in water, with the addition of a little alum, which promotes its solution: or a tincture is made from it with rectified spirit. This tincture is recommended also internally in the flor albus, and in rheumatic and scorbutic disorders: it has a grateful smell, and a not unpleasant, bitterish, all-ringing taste: in the Edinburgh pharmacopoeia, a tincture is directed to be made with spirit of scurvy grafts. The principal use of lac among us is in certain mechanic arts as a colouring drug, and for making sealing wax.