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, butour 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- 
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