324 THE VARIATION OF ANIMALS IN NATURE 



used by Eimer (1897) in practically the same sense as Haacke, 

 to denote a particular class of evolutionary phenomenon 

 which he had detected in his studies of Lizards and Lepidoptera. 

 As a result of his studies of the wing-pattern in the latter he 

 concluded that the modification of the pattern is determined 

 not by selection, but by the action of the environment upon 

 a determinate constitution which limits the possibility of 

 variation to certain definite evolutionary lines. There are 

 three distinct elements in Eimer's concept — the inherited 

 effect of modification by the environment, the predetermined 

 (gegebene) constitution of the organism, and the limitation of 

 variation to certain evolutionary lines. The ' parallel varia- 

 tion ' of later authors is not a cardinal point of his theory, 

 but (I.e. pp. 1 60-1) he pointed out its occurrence as a con- 

 sequence of his main theory. 



The term thus applied to a definite theory of evolution 

 has been given erroneously to two other principles. 



(1) Osborn (191 2) used it for his ' rectigradations,' i.e. 

 adaptive modifications ' rising continuously in straight lines,' 

 though he seems to have considered that the early stages of 

 such rectigradation were not necessarily adaptive. Lull (1917, 

 p. 176) considers that the importance of orthogenesis (sensu 

 stricto) lies in its ' making a start in modification ' which is 

 subsequently continued by selection. To trends of adaptive 

 development the term orthoselection was given, though, as Lull 

 points out, selection obviously produces (at least theoretically) 

 determinate lines of evolution, so that that term is plainly 

 redundant. 



(2) The term is sometimes given to a capacity for pro- 

 gressive development inherent in the organism itself which 

 is independent of external influences. This is the Vervollkomm- 

 nungsprinzip of von Nageli (1883). It is obviously distinct from 

 those just mentioned and involves a totally distinct evolutionary 

 principle which will be discussed at a later stage in this chapter. 



Mention should also be made here of Cope's principles 

 of kinetogenesis and archaesthetism (1887), which he formu- 

 lated in accordance with his belief in the creative effects of 

 use and disuse and the determining influence of consciousness 

 over animal form. Cope's views, which were founded on his 

 palaeontological experience and embody a remarkable antici- 

 pation of certain modern ideas, are primarily Lamarckian ; 



