HISTORICAL SKETCH 44S 



155): "The proposition determined on after much consideration 

 is, that the several series of animated beings, from the simplest 

 and oldest up to the highest and most recent, are, under the provi- 

 dence of God, the results, first, of an impulse which has been im- 

 parted to the forms of life, advancing them in definite times, by 

 generation, through grades of organization terminating in the 

 highest dicotyledons and vertebrata, these grades being few in 

 number, and generally marked by intervals of organic character, 

 which we find to be a practical difficulty in ascertaining affinities; 

 second, of another impulse connected with the vital forces, tend- 

 ing, 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 'adapta- 

 tions' of the natural theologian." The author apparently believes 

 that organization 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 be- 

 come adapted to its peculiar habits of life. The work, from its 

 powerful and brilliant style, though displaying in the early edi- 

 tions little accurate knowledge and a great want of scientific cau- 

 tion, immediately 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 I'Acad. 

 Roy. Bruxelles," tom. xiii. p. 581) his opinion that it is more 

 probable 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 Association, 

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

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



