2 Where did Life Begin ? 



migratory and nomadic. The individuals may 

 be rooted and stationary, but the tribe is trav- 

 elHng, constantly leaving old fields and sur- 

 roundings and as constantly arriving in new 

 ones, sometimes crowded out, sometimes 

 starved out, and sometimes invited out, but 

 always moving. Moving on to a new envi- 

 ronment, better suited, taking all things into 

 consideration, to satisfy the pressing needs of, 

 and to develop and raise in the scale of being, 

 both the individual and the species. 



A second great truth taught by examining 

 the methods of these movements and study- 

 ing the causes of this ceaseless tramp of or- 

 ganic life is, that certain essential elements of 

 the environment itself are usually found to be 

 travellino; with or a little in advance of the 

 migratory species. In other words, the rainfall 

 and isothermal lines, the climatic and other 

 conditions of life, are constantly and slowly 

 changing relative to the locality, but moving 

 in fact. It has been frequently observed that 

 certain species, occupying some particular ter- 

 ritory now, have at some recent time in the 

 past been enabled by such changes to crowd 



