42- NATURAL SCIENCE. January. 



seems to be needed by Professor Cope, For he says (p. 7) " Mr. 

 Spencer occasionally falls into the error of ascribing the origin of 

 structures to natural selection, as in the case of the forms of flowers 

 (Principles of Biology, II, p. 153), and the armor-plates of paleozoic 

 fishes {Op. cit. p. 288)." What Mr. Spencer does say is (on p. 153), 

 " if we bear in mind the functions of flowers, we shall find in their 

 adaptations to their functions, under conditions that are extremely 

 varied, an adequate cause for the different types of symmetry, &c.," 

 and again, "the forms and positions of those subsidiary parts which 

 give the general shape to the flower, similarly arise by the survival 

 of individuals which have the subsidiary parts so adjusted as to aid 

 this fertilizing process." And what Mr. Spencer says on p. 288 is, 

 " The contrasts between .... soft skin Fish and P'ish in armour 

 like the Pterichthys, must have been produced entirely by natural 

 selection." Moreover, on page 192 Professor Cope says that Wallace 

 ascribes the colour and form characters of animals " to natural selec- 

 tion as a cause." This time no reference is given, so one can merely 

 draw attention to the fact that nothing in Mr. Wallace's book 

 " Darwinism " supports this statement ; on the contrary, its author 

 continually postulates the existence of variation before selection, he 

 accepts sexual reproduction as the main, if not the only, cause of 

 variation, and, as for colour, he regards it " as a normal product of 

 organisation, which has either been allowed free play, or has been 

 checked and modified for the benefit of the species " (p. 299). 



From the point of view of the argument, the third part of the 

 book, entitled " The Inheritance of Variation," is by far the most 

 important ; for by " variation " Professor Cope usually means what is 

 here called " modification." If the inheritance of modification be 

 proved in a single instance, then it is a possibility, and as such may 

 legitimately be drawn upon in constructing a theory of organic evolu- 

 tion. Is it proved here ? The first argument is that certain characters 

 were, at some time or other in the history of each line of descent, 

 acquired, i.e., they first appeared as modifications of adult structure ; 

 and that these characters are no longer induced afresh in each gener- 

 ation, but are inherited. In short, " all characters now congenital have 

 been at some period or another acquired." For instance, the groove-joints 

 between the metapodial bones and the phalanges of the mammalian 

 foot are assumed to have been due origmally to mechanical causes ; 

 they are no longer so due, since they are to be found prefigured in 

 cartilage in young animals that have never stood on their feet. The 

 Neo-Darwinian sees no difficulty here: first, he simply denies that such 

 characters were originally produced by mechanical causes ; secondly, 

 he maintains that, even if they were so produced, yet the inherited 

 characters were really congenital variations that happened to be in 

 the same direction as the modifications. It is clear that such an 

 argument cannot be disproved, so we pass, with our author, to the 

 evidence from palaeontology. Here Professor Hyatt entirely fills the 



