TIME AND CHANGE 
ward through the invertebrates, through the fish, 
through the reptile, through the lower mammals, 
through his simian ancestors till he reaches his goal 
in the man we know. 
Darwin was not the author of the theory of evolu- 
tion, but he made the theory alive and real to the 
imagination. He showed us what a master key it is 
for unlocking the riddle of the life of the globe. 
He launched biological science upon a new career 
and made it worthy of its place in the great trilogy 
of sciences, astronomy, geology, and biology, of 
which Tennyson, in his poem “Parnassus,” recog- 
nized only the first two. Had Tennyson written his 
poem in our day he would undoubtedly have in- 
cluded biology among his “terrible Muses” that 
tower above all others, eclipsing the glory of the 
great poets. Or is it true that we find it easier to 
accept the theory of the evolution of the worlds and 
suns from nebulous matter than to accept the theory 
of the evolution of man from the maze of the lower 
animal forms? It is less personal tous. The astro- 
nomer has the advantage of the biologist in one im- 
portant respect: he can show us in the heavens now 
the process of the evolution of worlds actually 
going on, but the biologist cannot show us the trans- 
formation of one species into another taking place 
to-day. We can sound the abysses of astronomic 
space easier than we can sound the abysses of geo- 
logic time. The stars and the nebule we have 
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