BEIEF ESSAYS 197 



imply greater volume and activity in past ages of 

 the physical forces that have shaped the earth, they 

 are doubtless true. In the Tertiary age these forces 

 became much more gentle and uniform in their 

 workings. As changes in the earth's surface would 

 be the most powerful factor in bringing about 

 changes of species, we see why new species seem to 

 have made their appearance so suddenly in early 

 geologic times. 



There can be but little doubt that the earth has 

 at last reached the maturity of her powers. She is 

 like a ripe apple upon the bough. Henceforth its 

 excellence must slowly decline. The game of life 

 upon this planet has been essentially played. That 

 is, no new developments remain, no new species on 

 any extended scale, as in the past, are to appear. 

 The bird has been evolved from the reptile, but the 

 bird is doubtless the top of that branch of our tree 

 of life; no new form is to be evolved from the 

 bird. We know pretty well the evolution of the 

 horse; he has arisen through various lower and 

 lesser forms, but probably nothing is to come after 

 the horse. The same with other forms. No higher 

 form is to succeed man, as he has succeeded the 

 lower. Monkeys and ourangs are left behind; they 

 will not give birth to a being superior to them- 

 selves; they are twigs that have been outstripped 

 by other and more favored branches. Man is the 

 last of the series. Superior races may arise, but not 

 a new and superior type of being. And it is very 

 doubtful about the superior race; there are those 



