THE SEED 7 
minating grains of barley, wheat, corn, rice, etc. By the 
presence of diastase starch is converted into grape sugar, a 
substance which is readily soluble in water, and which can 
be diffused easily through the tissues of the plant to any 
part where it is needed. In this way food travels from the 
leaf, where it is made, to 
the seed, where the sugar is 
generally reconverted into 
starch and stored up for 
future use, though some- 
times, as in the sugar corn 
and sugar pea, it remains 
in part unchanged. The 
kernels of this kind of corn 
can be distinguished readily 
from those of the ordinary 
starch corn, after maturity, 
by their wrinkled appear- d 
ance, owing to their greater Fic. 12.—Starch grains of wheat in 
loss of water in drying. different stages of disintegration under the 
action of a ferment (diastase), accompany- 
10. Food tests. —In or- ing germination: u, slightly corroded ; b,c, 
der to tell whether any of a d, more advanced stages of decomposi- 
the food substances named 
occur in the seeds that we are going to examine, it will be 
necessary to understand a few simple tests by which their 
presence may be recognized. The chemicals required can 
be ordered ready for use from a druggist or may be prepared 
in the laboratory as needed, according to the directions 
given. Write in your notebook a brief account of each ex- 
periment made, with the conclusions drawn from it. 
EXPERIMENT 1. TO DETECT THE PRESENCE OF FATS. — Rub a small lump 
of butter or a drop of oil on a piece of thin white paper. What is the effect ? 
ExpERIMENT 2. ANOTHER TEST FOR FATS. — Place some macerated 
alcanna root in a vessel with alcohol enough to cover it, and leave for an 
hour. Add an equal bulk of water and filter. The solution will stain 
fats, oils, and resins deep red. 
