302 THE FOUR INSEPARABLE FACTORS OF EVOLUTION. 



In other words, in the first generation at least heredity is not affected, and since 

 the experiment was conducted under artificial conditions, there was no selection. 

 The experiments concurred with the observation of naturalists that the pig- 

 mentation of the plumage of certain birds is intensified in regions of warm and 

 humid atmosphere. In Scardafella inca, on which the most complete series of 

 experiments was made, the changes took place only at the moults, whether 

 normal and annual or artificially induced at shorter periods. There was a corre- 

 sponding increase in the choroidal pigment of the eye. At a certain advanced 

 stage of feather pigmentation a brilliant iridescent bronze or green tint made 

 its appearance on those areas where iridescence most often occurs in allied 

 genera. Thus, as Beebe remarks, in birds no less than in insects characters 

 previously regarded as of taxonomic value can be evoked or withheld by the 

 forces of the environment. 



Another example may be given from Castle 



i 



"Conditions other than the character [heredity] of the gametes themselves may determine the 

 extent to which a character developes in the zygote, i. e., the completeness or incompleteness of its 

 dominance in a particular case. For example, in salamanders, which apparently, like mammals, form 

 skin-pigments of different sorts, such as yellow, brown, and black, Tornier has found that by feeding 

 (environment] one may control the proportions in which chromatophores of the several sorts are 

 formed in the skin. Abundant feeding causes preponderance of pigment [ontogeny] of one sort, scanty 

 feeding causes preponderance of pigment of another sort. Here external conditions determine the 

 degree of development of characters ..." (pp. 101-102). 



3. Initiation in Ontogeny. 2 



Some of the best illustrations of initiation in ontogeny are those which may be 

 selected in connection with the hypothesis of " organic selection" or "coincident 

 selection," independently formulated at the same time by Baldwin, Morgan, and 

 Osborn. Baldwin's statement of the hypothesis is as follows: 3 



■ 



Organic (or Indirect) Selection: Ger. organische or indirekte Selektion; Fr. selection organique 

 or indirecte; Ital. selezione organica or indiretta. The theory that individual modifications or accommo- 

 dations may supplement, protect, or screen organic characters and keep them alive until useful con- 

 genital variations arise and survive by natural selection. Cf . Coincident Variation, and Modification. 

 The theory of evolution which makes general use of organic selection is called Orthoplasy (q. v.). 



The theory, it is evident, involves two factors: (1) the survival of characters which are in any way 

 assisted by acquired modifications, &c, during periods in which, without such assistance, they would 

 be eliminated — until (2) the appearance and selection of congenital variations which can get along 

 without such assistance [pp. 1 13-1 14]. 



In the words of Osborn: " Individual or acquired modifications in new circumstances are an 

 important feature of the adult structure of every animal. Some congenital variations may coincide 

 with such modifications, others may not. The gradual selection of those which coincide (coincident 



i 



Op. cit., pp. 101-102. Insertions 

 Osborn, H. F. : Abstr. f A Mode of 



Inherit 



ance of Acquired Characters.] Trans. N. Y. Acad. Sri., vol. XV, Mar. 9 and Apr. 13, 1896, pp. 1«- 

 142, 148. Organic Selection, Science, N. S., vol. VI, No. 146, October 15, 1897, pp. 683 ~ M7 ' ? 

 Limits of Organic Selection, Amer. Naturalist, vol. XXXI. No. 371. Nov. 1893, pp. 944-951. Modi- 



Limits of Onranic Selection: A Joint Discussion with 



Oxford 



(Meeting of August, 1897), p. 239. 



Science, N. S., vol. XXVII, No. 697, May 8, 1908, pp. 749-752 



mm*, rroc. Amer. Assoc. Adv. Sci., vol. XLVI, June, 1898 

 Coincident Evolution through Rectigradations (third paper;, 



Baldwin. J. Mark 



Macmillan Company, 1902, pp. 213-214 



Dictionary of 



and Psychology 



