52 
MORPHOLOGY OF THE CELL. 
to Starch-grains in their appearance, and surrounded by a more or less homo- 
geneous matrix, which, as closer investigation shows, consists, according to the 
oiliness of the seed, of more or less oil combined with proteids. The grains 
themselves, on the other hand, consist, independently of certain enclosed matters, 
of proteids. 
In the aleurone-grains the proteid itself must be distinguished from the 
enclosed substances. The latter are either crystals of calcium oxalate, or non- 
crystalline, roundish, or clustered granules, known as Globoids. These are a double 
calcium and magnesium phosphate, in which the latter base is greatly in excess. 
Fig. 47. — Cells from the cotyledon in a ripe seed of Luptttus varins ; A in an alcoholic solution of iodine ; B after destruction 
of the aleurone-grains by sulphuric acid ; z the cell-wall ; p the protoplasmic matrix, containing but little oily matter ; y the 
aleurone-grains ; a drops of oil expelled from the matrix by the action of the sulphuric acid ; 7n empty spaces from which the 
aleurone-grains have been dissolved (X 800). 
The whole proteid is sometimes amorphous, and in that case is not doubly 
refractive; or the greater part, with the enclosed substances already named, is 
developed into a crystalloid (Sect. 7), and this, surrounded by a thin amorphous 
envelope, constitutes the aleurone-grain. (Fig. 48.) 
The proteids are all insoluble in water; neither alcohol nor water extracts 
anything from them. The grains which contain no crystalloids dissolve in water 
entirely {PcBonia), partially (^Lupinus), or not at all {Cynoglossum). But all dissolve 
completely in water containing only a trace of potash. With careful treatment there 
always remains behind a membrane surrounding the grain, which behaves like 
