Scope and Method 3 



' Evolution,* understood in the sense of the distinction 

 made immediately below. 



In furtherance of this object the most important distinc- 

 tion, at the very outset, is doubtless that upon which cer- 

 tain great departments of biological science are separated 

 off from one another: that between individual Develop- 

 ment and racial Evolution. It is Huxley to whom this 

 distinction of terms is attributed. Development is to be 

 used for the processes of the individual's history from the 

 beginning of its existence in the fertilized ^g^ to its death 

 — the province of fact also set off by biologists by the 

 technical term ' Ontogeny.' The province of racial de- 

 scent, the tree of connected forms springing from a 

 common stock, together with the entire series of forms 

 which may be represented as branches of the tree of animal 

 life on the earth, this province is that of Evolution, as 

 contrasted with Development — called by the biologists 

 technically ' Phylogeny.' The sciences of Embryology, Ex- 

 perimental Morphology, Physiology, etc., so far as they 

 are genetic, deal with Development ; those of Paleontology, 

 Comparative Morphology, etc., deal with Evolution. A 

 still more comprehensive province of research to which 

 the genetic method directly introduces us — whether we 

 deal with the data of mind or with those of Hfe — is that 

 of the interrelation or correlation of these two great 

 spheres. Development and Evolution, with each other. As 

 we shall see later on, certain most vital questions of gen- 

 etic science come up in connection with such a correlation.^ 



1 No single term has been generally adopted to cover the field of this cor- 

 relation between development and evolution. The term * ontophyletic ' (de- 

 termination, concurrence, etc.) might be employed, or the word * intergenetic,' 

 for cases in which both departments of genetic process are together involved. 

 See the remarks on page ii, note. 



