TIME AND CHANGE 



of life been easily equal to its own ends? True, the 

 clam remains a clam, and the starfish remains a 

 starfish; some other forms have carried the evo 

 lutionary impulse forward till it flowered in man. 

 Was this impulse ever really checked or endan 

 gered? Was the golden secret ever intrusted to 

 the keeping of any single form? and, had that form 

 been cut off, would the earth have been still with 

 out its man? These are puzzling questions. 



Thus, when we have come to look upon life and 

 nature in the light of evolution, what vistas are 

 opened to us where before were only blank walls! 

 The geologic ages take on a new interest to us. We 

 know that in some form we were even there. The 

 systems of sedimentary rocks which the geologist 

 portrays, piled one upon the other to a depth of 

 fifty miles or more, seem like the stairway by which 

 we have ascended, taking on some new and more 

 developed form at each rise. What we were at the 

 first step in Cambrian times only the Lord knows, 

 but whatever we were, we crept up or floated up 

 to the next rise. In the Silurian seas we may have 

 been a trilobite for aught we know; at any rate, we 

 were the outcome of the life impulse that begat the 

 trilobites, but our fate was not bound up with theirs, 

 as their race came to an end in those early geologic 

 ages, and our stem form did not. Whether or not 

 we were a fish in the Devonian seas, there is little 

 doubt that we had gills, because we have the gill- 

 226 



