_Problem.--What causes a young plant to grow?_ _(a) The relation of the young plant to its food supply._ _(b) The outside conditions necessary for germination._ _(c) What the young plant does with its food supply._ _(d) How a plant or animal is able to use its food supply._ _(e) How a plant or animal prepares food to use in various parts of the body._ LABORATORY SUGGESTIONS _Laboratory exercise._--Examination of bean in pod. Examination and identification of parts of bean seed. _Laboratory demonstration._--Tests for the nutrients: starch, fats or oils, protein. _Laboratory demonstration._--Proof that such foods exist in bean. _Home work._--Test of various common foods for nutrients. Tabulate results. _Extra home work by selected pupils._--Factors necessary for germination of bean. Demonstration of experiments to class. _Demonstration._--Oxidation of candle in closed jar. Test with lime water for products of oxidation. _Demonstration._--Proof that materials are oxidized within the human body. _Demonstration._--Oxidation takes place in growing seeds. Test for oxidation products. Oxygen necessary for germination. _Laboratory exercise._--Examination of corn on cob, the corn grain, longitudinal sections of corn grain stained with iodine to show that embryo is distinct from food supply. _Demonstration._--Test for grape sugar. _Demonstration._--Grape sugar present in growing corn grain. _Demonstration._--The action of diastase on starch. Conditions necessary for action of diastase. What makes a Seed Grow.--The general problem of the pages that follow will be to explain how the baby plant, or _embryo_, formed in the seed as the result of the fertilization of the egg cell, is able to grow into an adult plant. Two sets of factors are necessary for its growth: first, the presence of food to give the young plant a start; second, certain stimulating factors outside the young plant, such as water and heat. [Illustration: Three views of a kidney bean, the lower one having one cotyledon removed to show the hypocotyl and plumule.]