in THE RENASCENCE OF SCIENCE in 



for countless ages, was disturbing much besides, 

 English and German philosophers were formulating 

 the imposing theory which, under the name of the 

 Conservation of Energy, makes clear the inde- 

 structibility of both matter and motion. Then, to 

 complete the work of preparation effected by the 

 discoveries now briefly outlined, there appeared, 

 in the Leader, in its issue of 2Oth March, 1852, an 

 article by Herbert Spencer on the ' Development 

 Hypothesis/ in which the following striking passage 

 occurs : ' Those who cavalierly reject the Theory of 

 Evolution, as not adequately supported by facts, 

 seem quite to forget that their own theory is sup- 

 ported 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 animal organisms 

 numbering, of the one kind (according to Hum- 

 boldt) 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 vegetable 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 varieties 

 have been produced, as varieties are being produced 

 still ? . . . Even could the supporters of the Develop- 

 ment Hypothesis merely show that the origination of 



