RESPIRATION 
229 
205. Where Foodstuffs Are Stored in Seeds. — In the bean, 
we have seen that both carbohydrates and proteins were 
stored in the cotyledons, evenly distributed, so far as we can 
discover. In the endosperm of a corn grain, the carbohy¬ 
drates are under the scutellum, and the proteins in a 
distinct layer outside of the carbohydrates, covered by the 
flinty outside coat of the grain (see Figure 211). 
206. Digestion of the Food in the Seed. — It may appear 
strange that the growing bean plant lives upon the food stored 
in the cotyledons and yet such is the case. But this food must 
undergo a real digestion before the bean embryo can use it. 
We do not know just how this digestion takes place in the 
bean, but in the corn, as we have learned, there is a special 
structure, the scutellum, which helps to digest the food in the 
endosperm. This corn scutellum may be removed from the 
corn seed and made to digest other kinds of starch, for in¬ 
stance, that obtained from a finely grated potato. To 
show the action of the scutellum on potato, this should be 
kept warm and moist for several hours, after which the di¬ 
gested starch may be tested for sugar with Fehling’s solution. 
When scientists learn more about the digestive processes of 
plants they will probably find that they are similar to the 
same processes in animals. 
207. Respiration. — Germinate a handful of soaked peas 
or other large seeds in a bottle with a wide mouth. Fit the 
bottle with a rubber stopper with one hole in it. Bend 
into U shape a glass tube of suitable size to fit the hole, but 
with one arm longer than the other. Insert the short arm 
just through the stopper, and let the longer one dip into a 
beaker containing lime water. Set aside overnight. What 
is the appearance of the lime water? What gas causes this 
appearance ? Where does it come from ? Why are seeds used 
in this experiment ? (Answer after studying photosynthesis.) 
Boil a few ounces of water to drive out all the air. Cool 
it. Place some seeds in it and pour linseed oil over the top 
