We must be content here with the briefest outline of 

 the reply of science to these inquiries. 



I. Darwin invites his readers to "keep steadily in 

 mind that each organic being is striving to increase in 

 geometrical ratio." If this tendency were to continue un- 

 checked, the progeny of living beings would soon be un- 

 able to find standing room. Indeed, the very bac- 

 teria would quickly convert every vestige of organic mat- 

 ter on earth into their own substance. For has not Cohn 

 estimated that the offspring of a single bacterium, at its 

 ordinary rate of increase under favorable conditions, would 

 in three days amount to 4,772 billions of individuals with 

 an aggregate weight of seven thousand five hundred tons? 

 And the 19,000,000 elephants which, according to Darwin, 

 should to-day perpetuate the lives of each pair that mated 

 in the twelfth century — surely these would be a "magna 

 pars" in the sanguinary contest. When the imagination 

 views these and similar figures, and places in contrast to 

 this multitude of living beings, the limited supply of nour- 

 ishment, the comparison of nature with a huge slaughter- 

 house seems tame enough. But reason, not imagination, 

 as Darwini observes more than once, should be our guide 

 in a scientific inquiry. 



It is observed on careful reflection that Darwin's the- 

 ory is endangered by an extremely large disturbing ele- 

 ment, viz., accidental destruction. Under this term we in- 

 clude all the destruction of life which occurs in utter indif- 

 ference to the presence or absence of any individual varia- 

 tions from the parent form. Indeed, the greatest destruc- 



14 



