PROTOPLASM AND PLANT-OELLS. 11 
which are concentrically striated. Now add a small drop of iodine 
and note the blue coloration, which becomes purple or purple-black 
if much iodine is used. 
(0) Make an extremely thin slice of the potato-tuber and treat as 
before, so as to observe starch-grains in 
the cells. By staining such a section 
with carmine the protoplasm in the 
starch-bearing cell may be made evi- 
dent. 
(c) Study the starch of wheat, rice, 
Indian corn, oats, etc. 
(@ Mount carefully a few threads of 
Pond Scum (Spirogyra) which has been 
for some hours in the sunlight. Note 
the aggregations of minute starch-grains 
in the spiral chlorophyll-body (Fig. 6). 
Now add iodine and observe the color- 
ation of starch-grains. 
(e) Make thin sections of leaves which 
have been in the light for some hours, 
and observe minute starch-grains in 
the chlorophyll-bodies. Use iodine as 
above. 
(f) Make longitudinal sections of 
ripened apple-twigs and note the starch 
stored in certain cells of the pith for use 
when growth is resumed. 
24, Aleurone.—In mature seeds 
and tubers there are commonly to 
be found small rounded granules Si 
of albuminous matter to which the tiene cech aie wine ool 
a chlorophyll-bodies, eacb with ag- 
name of Aleurone has been given gregations of starch. Ata and 
(Fig. 5). It is, in part at least priparstery se uniine, Masa 
(Fig. 5). f EE ? Red 500 times. See 
the protein matter of the older 
botanists. It is also identical with what has been called 
the gluten of the grains of wheat, rye, oats, etc. 
25. Aleurone is poorly understood, but it appears to be 
a dry resting state of protoplasm. Some, if not all, of it 
