570* POPULAR SCIENCE MONTHLY. 



embryo had been divinely arranged, it would surely have gone 

 along lines of direct growth from the germ to the finished form : 

 would not have displayed various metamorphoses having no 

 relations either to passing needs or to ultimate structure and 

 mode of life. With which evidence may be joined the evidence 

 furnished by rudimentary organs, which are full of meaning on 

 the evolution hypothesis, but worse than meaningless in the spe- 

 cial-creation hypothesis. 



But these four great groups of facts, suggesting in different 

 ways the same history, stand thus far without assigned cause. 

 How come these progressive modifications to have taken place ? 

 and why are the modified forms connected with one another in 

 the ways shown alike by paleontology, by classification, by dis- 

 tribution, and by embryology ? The reply is that we need only 

 look around to see everywhere at work a general cause which, if 

 it has been at work throughout all time, yields an explanation. 

 Take any plant or animal and expose it to a new set of circum- 

 stances (circumstances not so unlike its previous ones as to prove 

 fatal), and it begins to change ; and the change is one which 

 eventually adapts it to the new conditions. By what special 

 causes the adaptive modifications are effected does not at present 

 concern us. Here the argument requires us only to recognize the 

 truth that in some way the organization is molded to the new 

 conditions. Though to illustrations furnished by cultivated 

 plants and domesticated animals it may be objected that arti- 

 ficial selection has been at work, yet, since artificial selection im- 

 plies variations, it implies that the selected plants and animals 

 have been modified by external influences, and that the modifica- 

 tions have been inherited and accumulated. And then, if there 

 needs a case in which artificial selection has not come into play, 

 we have a sufficiently striking one in the human race itself. 

 Unless there be adopted the hypothesis (excluded by Lord Salis- 

 bury's implied belief) that varieties of men have been independ- 

 ently created, the conclusion is irresistible that their differences 

 have been caused by unlikenesses in their lives carried on in un- 

 like environments. Either their differences are uncaused, which 

 is absurd, or they are differences which have -unfitted each varie- 

 ty for its conditions, which is also absurd, or they are differences 

 which have fitted each variety for its conditions ; and, if so, they 

 have resulted from the response of the constitution to the condi- 

 tions themselves : the only supposition which is not absurd. And 

 that this is the necessary interpretation is shown by cases in 

 which either by the killing off of unfit individuals, or by the 

 effects of habit, or by both extraordinary adaptations have been 

 produced. There are, as examples, the Fuegians, who in their 

 wretched islands go about naked while the falling snow melts on 



