LESSONS WITH PLANTS 343 



the whole earth. This migration may have been due to 

 circumstances, such as the unfavorable conditions of life in 

 the old home, the encroachment of more powerful neigh- 

 boring races, or the attraction of a region affording better 

 living, more freedom, etc. In many communities the con- 



Fig. 139. Sensitive Plant. 



( The leaf at the left was touched and was slowly closing during the exposure of the 

 negative. Hence the blurring.) 



ditions for making a living become intolerable or very diffi- 

 cult. Then the younger generations go to "pastures new." 

 Many of them are assisted by their parents financially and 

 by education to make this change. Generally the old peo- 

 ple cannot leave their homes and finally die there. Thus a 

 stock of people may die out in one place and appear again 

 in another. 



