56 MORPHOLOGY OF THE CELL. 



afterwards seen still extended. In Lup'inus luteus the crystal of calcium oxalate, which 

 is afterwards enclosed by the largest grain, is already present in the cell-sap before the 

 formation of the grains of proteine. Pfeffer was able to follow the development of the 

 grains with remarkable ease in the peony ; in this case the seed is still, even when it has 

 attained its full size, filled with large starch-grains, which become changed into oil only 

 when fully ripe ; or even when the seed has been removed from the carpel before the 

 reserve-materials have been completely introduced. The starch is not always, however, 

 completely changed into oily matter. If the starch-grains in the seeds of the peony are 

 imagined to be not completely transformed, and the intermediate mass, almost devoid of 

 oily matter but very rich in proteinaceous substances, forms very small grains of pro- 

 teine, we have what does actually occur in Phaseolus and in other seeds extremely rich 

 in starch. There are, however, also seeds in which proteine and starch- grains occur in 

 nearly equal quantities, but then always associated with oily matter. 



No argument can be founded on the turbid condition of the cell-contents and the 

 softness of the growing grains of proteine, with respect to the manner of growth. 

 Nevertheless it can mostly be affirmed with regard to ripe grains, that those situated 

 farther towards the inside are softer, and that, consequently, on the application of very 

 dilute reagents, they dissolve from within outwards. Different facts appear, never- 

 theless, to show that no growth takes place by intussusception, as with the grains of 

 starch. The origin of the grains of aleurone is simply a dissociation, which arises from 

 loss of water by the seed, and, on germination, the cell-contents first of all returns more 

 or less completely to the condition of a union of the matrix with the substance of the 

 grains of proteine. 



Pfeffer followed out the formation of the crystalloids in Ricinus and Euphorbia sege- 

 tum ; they arise nearly simultaneously with the globoids, at a rather early period, and both 

 grow gradually, while the turbidity of the cell-contents at first somewhat increases. They 

 mostly lie, even at an early stage, quite close to one another, but completely surrounded 

 by the turbid mass ; the vacuoli which Gris (Recherches sur la germination, PI. I, 

 Figs. 10-13) figures are the result of the very slight commencement of disorganisation 

 of the cell-contents. The crystalloids are from the first sharp-edged, and, as soon as 

 their size permits their form to be recognised, it agrees with that of the mature crystal- 

 loids. The envelopment of crystalloid and globoid by amorphous coatings follows first, 

 if the crystalloids are mature and the drying of the seed has commenced. 



With germination the crystalloids dissolve as well from without as from within, even 

 after the envelope has first disappeared ; the enveloping membranes are for a time per- 

 sistent, but gradually become invisible. The globoids also dissolve (no doubt in conse- 

 quence of the acid reaction which the tissue assumes), and in the case of old seeds 

 from the outside inwards. The grains of aleurone destitute of crystalloids next swell 

 up and resume, on the germination of the seed, the form which they possessed in ripe 

 but still watery seeds ; they then begin to mix with the substance of the matrix ; and 

 thus sometimes a definite dissolution can be followed from without inwards ; but they 

 often coalesce as mucilaginous masses. These changes occur with the first signs of ger- 

 mination in the embryo ; formation of starch then also takes place simultaneously in the 

 contents of the cells. 



Sect. 9. Starch Grains ^ — Plants which vegetate . under favourable cir- 

 cumstances produce by assimilation a larger quantity of new formative organ- 

 isable substance than they require or can employ at the time for the growth of the 

 cells. These materials are stored up in some form or other in the cells them- 



^ Niigeli, Die St"irkek6i-ner, in Pflanzenphys. Untersuchungen, Heft II, and Sitzungsber. der k. 

 bayer. Akad. der Wissenschaften, 1863.— Sachs, Handbuch der Exp. Phys. Leipzig 1865, § 107. 

 What I give here is essentially after Nageli's work. 



