242 VEGETABLE PHYSIOLOGY 
increase in size, growing inwards into the protoplasm as 
well as outwards into the vacuole, till they can be seen to 
be in the form of grains embedded in the protoplasm, which 
in consequence of their development assumes the appear- 
ance of a coarse network. As this process continues, the 
original grains growing in size, and new ones being con- 
stantly formed, the original vacuoles become obliterated 
and the cell swollen out by its own deposits (fig. 117). 
While this mechanical process is going on chemical changes 
also take place in the material secreted. The protoplasm 
forms protein originally at the expense of the amido-acids, 
sugars, &c., brought down to the cell, but the variety 
Fig. 117.—CELL or Rrez SzED oF Fie. 118.—Ceit oF Riornus SEED, 
Lupinus, FILLED WITH ALEURONE CONTAINING FrvE ALEURONE 
GRaIns. Grains. 
originally constructed is not necessarily the same as that 
subsequently stored. At first the grains are not soluble in 
either 10 per cent. or saturated solutions of common salt. 
Later on they can be dissolved by both of these fluids. 
The deposition of aleurone grains in the cell is thus, 
like that of starch, a process of secretion carried out by the 
protoplasm: a process, that is, of manufacture of the grain 
by the latter, after it has been supplied with less highly 
organised material. It is so constructed by the intervention 
of the protoplasm itself, the grain growing at the apparent 
expense of the substance of the latter. 
There is no doubt that the amorphous deposits of proteins 
in the cells of fleshy roots and stems are due to a similar 
process of secretion. 
