112 
MANUAIy OP NATURE) STUDY. 
the sap is done visiting the leaf or when it brings 
away the last load, the gate to the foot-stalk is 
forever closed and the leaf is ready to fall. If frost 
should come and find the gate open a raw place 
would be left v/here the leaf joined the branch, out 
of which sap would flow, and thus lose part of the 
winter’s food; but the plant seems to understand 
the situation, hence the closing of the gate or seal¬ 
ing over the place for protection. Why do leaves 
fall after a heavy frost? Are leaves of any benefit 
after they have fallen? How? What is the form 
of the food as stored in the bud for the winter? 
Starch. What change is brought about in the 
starch when the bud begins to swell in spring 
time? Sugar. Why is it necessary to change 
form? So that the sap can dissolve and use it. 
See lesson on saliva in fourth grade. 
The purpose of the bud is to furnish winter 
quarters for plant or flowers or both. The buds on 
the tree are a community of stem germs (baby 
plants). 
Compare cocoons of caterpillars with the hiber¬ 
nation of Johnny Jump Up or Spring Beauty. 
Where is the store of food in each case? Where 
in the tuber? Compare with hibernation of ani¬ 
mals, such as frogs, snakes, earth worms, etc., 
with the migration of birds. 
All nature acts upon one common plan, varying 
