HISTOKICAL SKETCH. Xvfl 



another impulse connected with the vital forces, tending, in the 

 course of generations, to modify organic structures in accordance 

 with external circumstances, as food, the nature of the habitat, 

 and the meteoric agencies, these being the ' adaptations ' of the 

 natural theologian." The author apparently believes that organi- 

 sation progresses by sudden leaps, but that the effects produced 

 by the conditions of life are gradual. He argues with much force 

 on general grounds that species are not immutable productions. 

 But I cannot see how the two supposed " impulses " account in a 

 scientific sense for the numerous and beautiful co-adaptations 

 which we see throughout nature ; I cannot see that we thus gain 

 any insight how, for instance, a woodpecker has become adapted 

 to its peculiar habits of life. The work, from its powerful and 

 brilliant style, though displaying in the earlier editions little 

 accurate knowledge and a great want of scientific caution, imme- 

 diately had a very wide circulation. In my opinion it has done 

 excellent service in this country in calling attention to the subject, 

 in removing prejudice, and in thus preparing the ground for the 

 reception of analogous views. 



In 1846 the veteran geologist M. J. d'Omalius d'Halloy pub- 

 lished in an excellent though short paper (' Bulletins de 1'Acad. 

 Roy Bruxelles,' torn. xiii. p. 581) his opinion that it is more prob- 

 able that new species have been produced by descent with 

 modification than that they have been separately created : the 

 author first promulgated this opinion in 1831. 



Professor Owen, in 1849 ('Nature of Limbs,' p. 86), wrote as 

 follows : " The archetypal idea was manifested in the flesh under 

 diverse such modifications, upon this planet, long prior to the 

 existence of those animal species that actually exemplify it. To 

 what natural laws or secondary causes the orderly succession and 

 progression of such organic phenomena may have been committed, 

 we, as yet, are ignorant." In his Address to the British Associa- 

 tion, in 1858, he speaks (p. li.) of " the axiom of the continuous 

 operation of creative power, or of the ordained becoming of living 

 things." Farther on (p. xc.), after referring to geographical dis- 

 tribution, he adds, "These phenomena shake our confidence in 

 the conclusion that the Apteryx of New Zealand and the Red 

 Grouse of England were distinct creations in and for those islands 

 respectively. Always, also, it may be well to bear in mind that 

 by the word ' creation ' the zoologist means ' a process he knows 

 not what.'" He amplifies this idea by adding that when such 

 cases as that of the Red Grouse are " enumerated by the zoologist 

 as evidence of distinct creation of the bird in and for such islands, 

 he chiefly expresses that he knows not how the Red Grouse came 

 to be there, and there exclusively ; signifying also, by this mode 

 of expressing such ignorance, his belief that both the bird and the 



