100 OBJECT LESSONS IN BOTANY. 
LESSON XXVI. 
LIFE OF THE PLANT, OR ITS BIOGRAPHY. 
204. Tuz water which the plant imbibes by its roots be- 
comes sap in the stem, and circulates in every part as the 
blood circulates in the animal frame. The leaves, by their 
broad, thin forms, serve as lungs, to bring all the sap which 
passes through them into contact with the air and light. 
205. By this means the sap is changed into a nourishing 
food, fitted to sustain the growth of the plant in every part. 
Thus the leaves are designed, not only as an ornamental robe, 
but as organs of breathing and digestion. 
206. In the second stage of growth, when the plant depends 
no longer upon the seed for nourishment, it goes on increas- 
ing in stature and multiplying its leaves and branches. It 
now consists of three parts, namely, root, stem, and leaves. 
These are called the organs of vegetation. 
207. The third stage of plant-life is the period of flowering. 
Before this period, all its activity was devoted to its own 
nourishment and growth. Now it begins to live and act for 
the continuance of its own kind after it upon the earth, 
according to the Divine decree in Genesis, i., 11. Some of 
its buds undergo a striking change, and open each a flower 
instead of a leafy branch. 
208. A. flower is therefore a leafy branch transformed (as 
204. What becomes of the water which the roots imbibe? What part do 
the leaves act? 
x, What change takes place in the sap? 
£06. What is the second stage of plant-life? 
207. The third stage? Whence come the flowers? 
