THE RENASCENCE OF SCIENCE. 121 



now defunct newspaper, the Leader, in its issue of 

 20th of March, 1852, an article by Herbert Spencer 

 on the Development Hypothesis, in which the fol- 

 lowing striking passage occurs: "Those who cava- 

 lierly reject the Theory of Evolution, as not ade- 

 quately supported by facts, seem quite to forget that 

 their own theory is supported by no facts at all. Like 

 the majority of men who are born to a given belief, 

 they demand the most rigorous proof of any adverse 

 belief, but assume that their own needs none. Here 

 we find, scattered over the globe, vegetable and ani- 

 mal organisms numbering, of the one kind (accord- 

 ing to Humboldt) some 320,000 species, and of the 

 other, some 2,000,000 species (see Carpenter); and 

 if to these we add the numbers of animal and vege- 

 table species that have become extinct, we may safely 

 estimate the number of species that have existed, 

 and are existing, on the earth, at not less than ten 

 millions. Well, which is the most rational theory 

 about these ten millions of species? Is it most likely 

 that there have been ten millions of special creations? 

 or is it most likely that by continual modifications, 

 due to change of circumstances, ten millions of varie- 

 ties have been produced, as varieties are being pro- 

 duced still? . . . Even could the supporters of the 

 Development Hypothesis merely show that the origi- 

 nation of species by the process of modification is 

 conceivable, they would be in a better position than 

 their opponents. But they can do much more than 

 this. They can show that the process of modification 

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