THE FOUR INSEPARABLE FACTORS OF EVOLUTION. 293 



1. Is it true that the greater number of new or germinal characters which 

 appear are orderly and according to some entirely unknown law of adaptation? 

 Or is it true that the greater number of new characters are accidental, disorderly, 

 fortuitous, adaptive or inadaptive, fitted or unfitted, and that order comes out 

 of chaos by the selection of those which happen to be fit? This question or 

 questions, as old as Empedocles, the crucial point in Darwin's philosophy, is 

 still a matter of investigation by the rigid analysis of the origin of new characters 

 in relation to the principle of the four factors. 



2. Is it true that the greater number of new characters of evolution first 

 appear in heredity; or is it rather true that the greater number of new characters 

 first appear in ontogeny and subsequently in heredity? 



3. Is it true that blastogenic evolution lags behind ontogenic or somatic in 

 certain structures, organs, and modes of change? 



4. What are some illustrations of the slow action of heredity, that is, where 

 heredity seems to lag behind ontogeny? What are some of the illustrations of 

 t he rapid action of heredity, that is, where heredity seems to precede or anticipate 

 ontogeny? 



5. Are differences first appearing in ontogeny identical with those which 

 subsequently appear in heredity? 



6. What primarily ontogenic characters become fixed in heredity and what 

 remain purely ontogenic? 



Special Aspects of Heredity. 



Repetition of type, the heredity par excellence of many authors, is equivalent 



to likeness of type, stability of type, breeding true to type, to the principle that 



like produces like, in short, to the conservative principle of heredity and a large 



number of expressions of this conservative principle. In studying environment 



and ontogeny it has been made clear, however, that repetition of type depends 



upon repetition of ontogeny, repetition of environment, and repetition of 

 selection. 



Correlations in heredity are (a) of similar or like parts, such as of strong 

 muscular and bony systems, or (b) dissimilar or unlike parts, as, for example, 

 the correlation of speed with bay color in thoroughbred horses. We now under- 

 stand through the laws of ''particulate inheritance" of Galton, or "unit char- 

 acter" inheritance of Mendel and of Bateson that characters depend upon 

 certain theoretic "determiners" in the blastos, the association of which conditions 

 these correlations. 



Fluctuations in Heredity. — These include in part the variations of Darwin, 

 variations of degree, plus and minus variations, the fluctuations around a mean, 

 the "continuous variations" of Bateson, the "allometrons," or differences of 

 proportion, of Osborn, so far as all of the above are blastogenic rather than 

 somatic in origin. 



The following notes as to fluctuations of character may be made: 





