280 



SCIENTIFIC AND APPLIED PHARMACOGNOSY 



of the drug is obtained from plants grown in England, Germany, 

 Holland and Italy. 



Description. Campylotropous, irregularly spheroidal, somewhat 

 compressed, 1 to 2 mm. in diameter, externally yellowish-brown, 

 seed-coat membranaceous, and minutely pitted, marked on one 

 side by a distinct ridge and two parallel furrows formed by the 

 hypocotyl and cotyledons; internally light yellow, without a reserve 

 layer, hypocotyl curved, cotyledons conduplicate; inodorous; taste 

 pungent and acrid. 



Inner Structure. See Figs. 126 and 127. 



FIG. 126. A, transverse section of Brassica alba (white mustard), ep, epidermis; 

 se, collenchyma; b, palisade layer of stone cells which have the inside and 

 lower portions of the side walls considerably thickened (so-called beaker 

 cells); p, several layers of parenchyma; P, aleurone layer consisting of thick 

 walls and having an oily cytoplasm and numerous very small, somewhat 

 spheroidal aleurone grains; i, layer of usually more or less compressed cells, 

 but here shown as being polygonal in outline. B, transverse section of Bras- 

 sica nigra (black mustard), ep, epiderms; se, collenchyma which are modified 

 to large giant cells and which give rise in part to the reticulations of the 

 seeds; b, palisade layer of peculiarly thickened stone cells (so-called beaker 

 cells) which are of unequal height; g, brown pigment layer consisting of 

 1 or 2 rows of cells which are tangentially elongated and colored blue with 

 solutions of ferric salts; K, aleurone layer consisting of thick walls and hav- 

 ing an oily cytoplasm and numerous very small, somewhat spheroidal 

 aleurone grains; o, several layers of more or less collapsed cells; c, cells of 

 embryo containing an oily cytoplasm and small aleurone grains, the latter 

 being either nearly spheroidal or somewhat ellipsoidal, and composed mainly 

 of globoids. After Moeller. 



Powder. (Fig. 127.) Light yellow; fragments of seed-coat 

 with mucilaginous epidermal cells; a sub-epidermal collenchymatous 

 layer of 1 or 2 rows of cells; a layer of radially elongated palisade 

 or stone cells (forming the so-called " beaker cells "), the walls of the 



