S4 VARIOUS FOOD-PLANTS 
Fic. 89.—Tomato. Flower, cut vertically, enlarged. Fruit, side view. 
Same, cut across. Seed, cut vertically to show curved germ, in seed- 
food. (Redrawn from Nees.) 
rid of as well as it can or allows to accumulate where they 
will do the plant no harm. The coloring matters and flavor- 
ing substances of the vegetables already studied are examples 
of such by-products. 
All of the chemical changes taking place in the living parts of an 
organism are together. called metabolism, the constructive changes 
being distinguished as anabolism,? and the destructive ones as catabo- 
1 Met-ab’o-lism < Gr. meta, beyond; ballein, throw. 
2 An-ab’o-lism < Gr. ana, upward. 
