THE WORM STRIVING TO BE MAN 



him. The mollusk remains, but some impulse went 

 out from the mollusk that begat the fish. The fish 

 remains, but some impulse went out from the fish 

 that begat the amphibian. The amphibian remains, 

 but some impulse went out from the amphibian that 

 begat the reptile. The reptile remains, but some 

 impulse went out from the reptile that begat the 

 mammal ; and so on up to man. Man must have had 

 a specific line of descent. One golden thread must 

 connect him with the lowest forms of life. And the 

 wonder is that this golden thread was never snapped 

 or lost through all the terrible vicissitudes of the geo- 

 logic ages. But I suppose it is just as great a wonder 

 that the line of descent of the horse, or the sheep, or 

 the dog, or the bird, was not snapped or lost. Some 

 impulse or tendency was latent or potential in the 

 first unicellular life that rested not till it eventuated 

 in each of these higher forms. Did any terrestrial or 

 celestial calamity endanger the line of descent of 

 any of the higher .creatures? Was any form cut off 

 in the world-wide crustal disturbances of the earth 

 at the end of palaeozoic and mesozoic time, when so 

 many forms of animal life appear to have been 

 wiped out, that might in time have given birth to a 

 kind unlike or superior to any now upon the earth? 

 Species after species have become extinct, whole 

 orders and families have gone out, often rather sud- 

 denly. Why we know not. Why the line of man's 

 descent was not cut off, who knows? It is a vain 



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