EDITOR'S INTRODUCTION xi 



majority of the subjects of general biology can be most profit- 

 ably treated in relation to a thorough general morphological 

 survey of the animal kingdom. This, I must confess, appears 

 to me pedagogically a most pernicious doctrine. It was all 

 very well so long as the other subjects remained scrappy. 

 But once they have penetrated deep enough to acquire definite 

 principles of their own, the defects of the method are revealed, 

 since it is almost impossible to teach two not very closely 

 related sets of principles simultaneously. This was soon 

 recognised for subjects with a definite body of principles of 

 their own, such as cytology or genetics ; but the old point 

 of view too often fingers in respect of, for instance, ecology, 

 or systematic and faunistic studies. 



The remedy, in my opinion, is to drop the whole notion 

 of having a single main course around which, like his para- 

 phernalia around the White Knight, the remainder of the 

 subjects are hung. There should be a series of courses of 

 approximately equal " value," each covering one of the main 

 fields of biological inquiry, each stressing a different set of 

 principles, so that the student will at the close have seen his 

 science from the greatest possible number of different angles. 

 As a preliminary programme, I should suggest about ten such 

 courses. For instance : (i) vertebrate morphology, stressing 

 the principles of comparative anatomy ; (2) vertebrate embry- 

 ology, stressing the principles of development, including 

 organogeny and histogenesis ; (3) the invertebrates and lower 

 chordates, stressing both comparative anatomy and embry- 

 ology, so as to bring out the divergencies and various grades 

 of animal fife ; (4) cytology and histology ; (5) genetics ; 

 (6) developmental physiology, including the effects of function 

 upon structure, regeneration, dedifferentiation, tumour- 

 formation, etc., as well as what is usually called experimental 

 embryology ; (7) faunistic zoology and ecology, bringing out 

 the types of environment, and of adaptations to various environ- 

 ments, as well as the *' animal sociology and economics " 

 covered by ecology in the narrower sense ; (8) comparative 

 physiology ; (9) animal behaviour ; and (10) evolution, 

 including some treatment of the principles of systematics. 



