Bet'ula al'ba, White Birch. -- Betulaceae; Olcum Betulae Empyreumaticum, Rectificatum, Rectified Oil of Birch Tar, N.F. The pyroligneous oil obtained by dry distillation of the bark and wood, rectified by steam distillation; Europs, Asia, N. Ameriaca. Large handsome tree. Oil is a limpid, dark brown liquid; odor penetrating, empyreumatic--resembling Russia leather; soluble in ether, chloroform, glacial acetic acid, amyl alcohol, oil of turpentine, benzene, carbon disulphide, dehydrated alcohol (3); mixed with alcohol (3) or purified petroleum benzene (3)--slight turbidity, but with methyl alcohol--decided turbidity, sp. gr. 0.918; aqueous filtrate 4 cc. + a drop of dilute ferric chloride solution (1 in 100)--green coloration, then brown, turbid (dist. from oil of cade); contains guiaiacol, creosol, cresol, xylecrol, phenol. Antiseptic counter-irritant; sore and stiffened muscles, joints; 1. Unguentum Resorcinolis Compositum, 6 p.c. B. Len'ta, Sweet Birch -- is one of the sources (bark) of U.S.P. Methyl Salicylate, see page 460; B. Papyrif'era, Paper (Canoe) Birch, white Birch; Canada, New York, has cordate leaves, tough white bark which separates into papery layers, and was used by the Indians in making canoes.