548 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



with the mycelia of a grayish mould ; outer surface of bark from which 

 the cork has been separated, light brown or reddish-brown and usually 

 more or less roughened; inner surface occasionally with adhering 

 wood, otherwise light yellowish-brown to light reddish-brown, longi- 

 tudinally finely striate and porous; fracture short-fibrous with pro- 

 jecting bast fibers; nearly inodorous; taste bitter and slightly 

 aromatic. 



Inner Structure. Bark consisting of a number of strands of 

 reddish-yellow cork, separated by large groups of stone cells, isolated 

 bast fibers and parenchyma; inner bark having starch-bearing 

 medullary rays, from 1 to 5 cells in width, separating narrow wedges, 

 composed of large proninent groups of stone cells in which are occa- 

 sionally included one or more thick-walled bast fibers, the latter 

 usually single, very thick walled, strongly lignified, and surrounded 

 with crystal fibers and starch-bearing parenchyma. 



Powder. Reddish-brown; bast fibers single, very long and 

 surrounded by crystal fibers, the crystals being in prisms frequently 

 terminated by pyramids, and from 0.008 to 0.030 mm. in length; 

 stone cells in large, thick groups composed of numerous more or less 

 tabular cells; cork cells more or less polygonal in outline with thick 

 slightly lignified walls; starch grains, from. 0.003 to 0.025 mm. in 

 diameter, single or 2- to 4-compound, the individual grains spheroidal, 

 ovoid or more or less plano-convex. 



Constituents. About 1.5 per cent of 6 different alkaloids, the 

 most important of which are aspidospermine, 0.17 per cent and 

 quebrachine, 0.28 per cent. Aspidospermine is colored brownish 

 with sulphuric acid and potassium dichromate, changing to cherry- 

 red or purplish. Quebrachine is colored yellow with perchloric acid. 

 The other alkaloids are: aspidosamine, which is colored blue by 

 sulphuric acid and potassium dichromate; aspidospermatine, which 

 is colored deep red by perchloric acid; quebrachamine, which resem- 

 bles quebrachine but has a much lower melting point; also hypo-- 

 quebrachine. In addition, quebracho contains 3.5 per cent of tannic 

 acid; a cholesterin-like body, quebrachol; a sugar, quebrachit; and 

 a white or greenish-white ash, about 10 per cent. 



Allied Plants. The bark of Aspidosperma Quebracho Colorado 

 contains 20 per cent of tannic acid. A commercial extract is made 

 from the bark, which is used in the tanning of leather. 



