ii4 SCIENCE PROGRESS. 



ripens the sap becomes less and less watery, and gradually 

 the proteid is deposited by a process of precipitation till the 

 complete aleurone grain is formed. 



The mode of formation thus indicated seems to show 

 that the process is altogether independent of the presence, 

 or at least the activity, of the protoplasm of the cell. So 

 important a matter as the storage of this form of reserve 

 seems hardly likely to be altogether without the control of 

 the living substance, particularly in the light of Schimper's 

 observations on the mode of formation of starch grains in 

 similar situations. Some careful researches carried out 

 much later by Rendle (2) point to an altogether different 

 mode of formation, at any rate in leguminous seeds, in which 

 aleurone grains are extremely conspicuous. The material 

 used by the latter observer was the seeds of species of 

 Lupinus, his chief research being upon L. polyphyllus. The 

 early stages of construction of the grains were only observ- 

 able when the development of the cotyledons was suffi- 

 ciently advanced to swell out the seed coat, by which time 

 the endosperm had been absorbed. At this time the peri- 

 pheral layer of protoplasm contained chlorophyll grains, in 

 the substance of which starch was fast accumulating. While 

 the store of carbohydrate food was thus being packed away 

 the aleurone grains gradually became observable. Rendle 

 lays stress on the fact that they first appeared as, or were 

 preceded by, small bodies of spherical or ovoid shape which 

 projected from the protoplasm. In some cells the latter 

 only existed as a peripheral layer, in others it appeared also 

 as bridles crossing the vacuole. Wherever the seat of 

 formation could be noticed its first sign was this protoplas- 

 mic protrusion. Little by little these projections increased 

 in size, growing inwards as well as outwards, till the grains 

 could be seen as ovoid or spherical bodies embedded in 

 the protoplasm, which, in consequence of their development, 

 assumed the appearance of a coarse network. Gradually, 

 as the process thus went on, the older grains increasing in 

 size and newer ones being subsequently formed, the original 

 vacuole became obliterated and the cell was swollen out by 

 its own deposits. This mechanical process was accompanied 



