588 NATURE STUDY. 



LESSONS III. AND IV. GROWTH, USES, AND ADAPTATION 

 OF ROOTS. 



Preparatory work. Watch, if possible, growth of roots of 

 seeds on damp blotting-paper in glasses. Note increase in 

 length and formation of branches. Possibly the formation of 

 root hairs may be seen. Dig up from soil a few plants two 

 or three weeks old, being careful not to disturb the roots, 

 and carefully wash off the soil. Try to show that the roots 

 always grow downward, by experiment suggested in outline 

 on bean. Mark with point of fine needle, dipped in ink, 

 minute dots on the root, the first as near to the tip as pos- 

 sible, the others at intervals of an eighth of an inch or less. 

 The experiment, if successful, will show that the root in- 

 creases in length only just back of the tip. If it kept 

 lengthening throughout its whole extent, it would be con- 

 stantly disturbing or pulling out its branches. The success 

 of these experiments depends largely on keeping the roots, 

 and particularly their tips, always moist. 



Step I. Growth of root. Trace its growth from the time 

 the first little " foot " was pushed out until branches were 

 formed on all sides. Impress fact of its always growing 

 downward. Discuss (if it has been seen, but not other- 

 wise) its manner of lengthening. 



Step II. Appearance and parts. Draw on blackboard, 

 directed by pupils, a well developed root, with branches 

 (and if seen, root hairs). 



Step III. Work or use or functions. Recall substances 

 that dissolve in water, perhaps including the lime which 

 forms the incrustation in the tea-kettle. Show how string 

 or blotting-paper draws up water, with what is dissolved in 

 it. The roots do the same. If the roots of young vigorous 

 morning-glory plants are placed in water with some red dye, 



