Tsu'ga (Abies) canaden'sis, Pix Canadensis (Canada Pitch, Hemlock Pitch). -- Prepared resinous exudation, U.S.P. 1830-1880; N. America. Hemlock struce is an evergreen tree 18-24 M. (60-80 degrees) high, .6-1 M. (2-3 degrees) thick, trunk straight, uniform size for 12-15 M. (40-50 degrees), bark rough, leaves 18 Mm. (3/4') long, 2 Mm. (1/12') wide, in 2 rows, numerous, glaucous, silvery beneath, cones ovate, 2.5 Cm. (1') long, resin (oleoresin) reddish-brown, translucent, or opaque, nearly hard, brittle, fracture shining, conchoidal; odor mild, balsamic, terebinthinate. Oleoresin is obtained by exudation, incision, or boxing; yield small. Used as stimulant, irritant, in plasters. Emplastrum Picis Canadensis, U.S.P. 1860-1880.