BY HEBER A. LONGMAN. 29 



from the many gill-bearing partitions of a shark to the 

 fewer and more highly-finished c()mi)-shaped gills of a 

 Telostean fish."* 



Kellogg writes of believers in a kind of Orthogenesis, 

 implying that "' organic evolution has been, and is now, 

 ruled by unknown inner forces inherent in organisms, 

 and has been independent of the influence of the outer 

 world. The lines of evolution are immanent, unchangeable, 

 and ever slowly stretch towards some ideal goal."!' Such 

 a belief savours more of abstract philosophy than of science . 



J. M. Baldwin, recognising the difficulties associated 

 with the term Orthogenesis, used the term Orthoplasy.J 

 thus suggesting a freer play of the laws of natural selection. 

 But this term is inadequate to typify the facts. The 

 phenomena of variation are wider than any of the theories . 



Very concisely I have endeavoured to enumerate a 

 number of other standpoints. Hans Driesch formulated a 

 view which suggests a kind of " directive soul " for organ- 

 isms, an ■■ entelechy " operating on its course of variations- 

 Samuel Butler and Semon propounded a theory of organic 

 memory, and the latter opines that the results of stimuli 

 can never be wholly lost. The quintessence of Weis- 

 mannism is a struggle between hereditary forces, with 

 nutrition as a contributory factor. De Vries looks upon 

 nutrition as a dynamic of individual variability and muta- 

 tion, and here may be gathered much evidence from many 

 practical experimenters. Of intense interest are the 

 researches of Loeb and Poulton who have recorded many 

 experiments — the former chiefly with marine invertebrates 

 and the latter mostly with the pupal stages of insects — 

 which apparently dononstrate that variation, and even 

 the life form itself mechanically react to chemical and other 

 external processes. The experiments of C. W. Beebe. 

 New York Zoological Society, are illuminating in the same 

 respect with relation to Passerine bii'ds. He shows that 

 alterations in temperature and food are accompanied bv 

 changes in plumage and in the moulting season, and that 



*Pies. Ad. Zool. Sect. Brit. Assn., 1913. 



t" Danvinism To-day," p. 278. 



J Quoted by Osborn. Op. cit. post. 



