16 NATURE SKETCHES IN TEMPERATE AMERICA 



under given conditions that decides the permanence of a form. 

 Variation is sometimes orderly tendency, — that is, there is 

 definite variation, — or the species forming variability and 

 mutabihty is indeterminate in direction. In either case 

 it is not teleology, or adaptation to purpose, which was so 

 effectually eUminated by Darwin. We find there is apparent 

 difficulty for natural selection to account for the incipient 

 stages of useful organs, and here orthogenesis attempts to 

 remove this obstacle. The name was originally introduced 

 by Haache, and later, among others, was championed by Eimer. 

 The latter 's work was dominated by a desire to show the 

 inheritance of acquired characters. 



Whitman ^ says that "without the assistance of some factor 

 having more continuous directive efficiency, .selection would 

 fail to bring out of the chaos of chance variation or kaleidoscopic 

 mutation, such progressive evolution as the organic world 

 reveals. In order to show such a factor is essential, and that 

 it is actually present, supi)lying the indispensable initial stages, 

 and holding the master hand in the general direction of evo- 

 lution, demonstrative evidence is. of cour.se. required. Such 

 evidence lies in the history of specific characters.'' After pains- 

 taking breeding experiments with pigeons covering many 

 years. Whitman demonstrated by making phylogeny his guide 

 as a starting i)oint, that the orthogenetic jjroce.ss is a primary 

 and fundamental one. By his researches, he found it compara- 

 tively easy to thread liis way through tl;e maze of color patterns 

 existing among five hundred or more .species of pigeons, and 

 even to trace affinities farther back in the bird world. 



Of the orthogenetic process he further says: "We find 

 unlimited oi)j)ortunity for the j^lay of natural selection, escape 

 the great difficulty of incipient stages, and readily understand 

 why we find so many conditions arising and persisting without 

 any direct help of selection." 



O-sborn ~ has recently given the influences which govern 

 evolution as follows: "The life and the evolution of organisms 

 continuously centre around the proce.s.ses which we term 



' "The Problem of the Oripin of Species," Congress of Arts and Science, 

 Universal Exposition, St Louis, 1904. 



"Osborn in "Fifty Years of Darwinism," 1909, p. l238. 



