116 SAVAGE SURVIVALS 



ferent kinds of coal were formed. Hard coal is 

 different from soft coal because it has had differ- 

 ent experiences. 



AVe used to believe that mountains and river 

 valleys had always existed just as we find them. 

 But you know better since you studied physiogra- 

 phy. You know that river valleys have been filed 

 out by the rivers that flow thru them. And you 

 know that mountains have been lifted up and 

 sculptured by weathering and erosion into the 

 forms of today. And it is the same way with hu- 

 man nature. It has grown to be what it is. And 

 in this sub-course I want to teach you something 

 about the origin of some of the instincts that are 

 found in our natures. 



Many of the most powerful tendencies in the 

 natures of higher peoples are vestigial. They are 

 tendencies which were useful in the earlier and 

 more primitive ages of the world, but w^liich, ow- 

 ing to changed conditions, are no longer useful. 

 They persist as parts of our nature m accordance 

 with the same laws of survival which perpetuate 

 the vermiform appendix, the ear muscles, and 

 other useless parts of the human body. Darwin 

 says that man has in his body about eighty dif- 

 ferent parts that are vestigial — eighty different 

 parts that are of no use whatever. And it is very 

 certain that there is a much larger proportion of 

 our natures that is vestigial than of our bodies. 

 We have a great deal of lumber in our bodies, but 

 much more in our minds and natures. 



