576 BOTANY AND PHARMACOGNOSY. 



from 0.5 to I mm. long. Grain nearly smooth, grooved on one 

 side and with a slight projection at the apex consisting of numer- 

 ous I -celled hairs, usually with pollen grains adhering, embryo 

 on side opposite the groove and forming a slight projection at 

 the base of the grain ; endosperm large and consisting chiefly of 

 cells filled with spherical starch grains resembling those of wheat, 

 the two to four outer layers of cubical cells containing aleurone 

 grains. The embryo is connected with the endosperm by means 

 of a sheathing membrane (by some regarded as a modified coty- 

 ledon), through which it obtains nutriment during germination. 

 ( )n germination the embryo produces about 5 multiple primary 

 rootlets and a stem portion with sheathing green leaves (Fig.321). 



Malt. Grains resembling those of barley, of a yellowish- 

 brown to dark brown color, and with a short fracture ; starch 

 grains altered, exhibiting numerous radial and concentric fissures ; 

 odor agreeable and taste sweetish. 



Constituents.- Barley grains contain from 60 to 68 per 

 cent, of starch; 12 to 18 per cent, of proteins; about 1.5 per cent, 

 of sugar, and i to 3 per cent, of fixed oil. Two ferments are 

 developed during the process of germination, namely, diastase, 

 which acts on the starch, changing it to dextrin and maltose ; and 

 another ferment which acts on the proteins, converting them into 

 peptones. The germinating seeds of barley contain a white crys- 

 tallizable alkaloid, hordenine, which is slightly toxic. 



Commercial malt contains nearly the same constituents as 

 are found in barley, the starch grains being somewhat altered 

 and converted partly into soluble starch through the action of the 

 ferment diastase, a small amount of which is still present in malt 

 after drying. In the preparation of the extract of malt the 

 starch is mostly converted into dextrin and maltose, the propor- 

 tion of the latter being larger. 



PRUNUM. PRUNE. The fruit of Primus domestica, and 

 of the var. Juliana (Fami. Rosacese), a small tree (p. 287) indig- 

 enous to Southern Europe, and largely cultivated in Southern 

 France, Germany, Asia Minor and California, but not found 

 growing wild. The fruit is collected when ripe and partially 

 dried by artificial means, or completely dried in the sun. The 

 fruit exported from Bordeaux is of superior quality. 



