THE STORAGE OF RESERVE MATERIALS 248 
In many seeds, among which may be mentioned those 
of the Castor-oil plant and the Brazil nut, the aleurone 
grains possess a more complicated structure. Fig. 118 
shows a section of one of the cells of a seed of the castor- 
oil plant in which some of them are lying. The figure 
represents the cell after treatment with alcohol, and sub- 
sequently with water. The alcohol removes the oil with 
which the cells are filled, and which obscures the appear- 
ance of the grains. The latter are of ovoid shape, and as 
they lie their structure is not apparent. Water dissolves 
part of the outer portion, leaving visible the ovoid body, 
which becomes transparent. Embedded in it are a large 
regular crystal of protem matter, and a small rounded 
irregular mass consisting mainly of minute crystals of mineral 
matter. These two constituents are spoken of as the 
crystalloid and the globoid respectively. The part of the 
matrix which is not soluble in water will dissolve in a 10 
per cent. solution of common salt, while the crystalloid is 
soluble only in a saturated solution. The mineral part of 
the globoid of the grains of the castor-oil plant is a double 
phosphate of magnesium and calcium. 
Examination of these graing and their reactions shows 
that several proteins can be detected in them. Those 
soluble in water are proteoses, while the others which 
dissolve only in salt solutions are globulins. In grains 
met with in other plants, metaproteins occur which dissolve 
only in dilute alkalies. 
Crystals of protein occur in other places than seeds. 
If we examine a young potato, we find, in certain cells 
lying a little below the skin, some regular transparent 
cubical crystals, which are composed apparently of the 
same material as the crystalloids of the complex aleurone 
grains described. They are soluble in saturated solutions 
of common salt. Similar crystals are met with in the 
tissues of certain seaweeds. Many of them can be made 
to erystallise from the solvents which are used to extract 
them, 
16 * 
