432 TROPICAL NATURE vil 
advance, man’s intellectual and moral development reached 
almost its highest level in a very remote past. The lower, 
the more animal, but often the more energetic types have, 
however, always been far the more numerous; hence such 
established societies as have here and there arisen under the 
guidance of higher minds have always been liable to be swept 
away by the incursions of barbarians. Thus in almost every 
part of the globe there may have been a long succession of 
partial civilisations, each in turn succeeded by a period of 
barbarism ; and this view seems supported by the occurrence 
of degraded types of skull along with such “as might have 
belonged to a philosopher,” at a time when the mammoth and 
the reindeer inhabited southern France. 
Nor need we fear that there is not time enough for the 
rise and decay of so many successive civilisations as this view 
would imply, for the opinion is now gaining ground among 
geologists that paleeolithic man was really preglacial, and that 
the great gap (marked alike by a change of' physical condi- 
tions and of animal life) which in Europe always separates 
him from his neolithic successor, was caused by the coming 
on and passing away of the great ice age. 
If the views now advanced are correct, many, perhaps 
most, of our existing savages are the successors of higher 
races ; and their arts, often showing a wonderful similarity in 
distant continents, may have been derived from a common 
source among more civilised peoples. 
