xii EDITOR'S INTRODUCTION 



I do not wish to imply that each of these courses should 

 require the same number of lectures, still less the same amount 

 of practical work. But I do claim that each of them is in a 

 certain real sense of equal importance, since each of them, if 

 properly taught, can impart its own characteristic point of 

 view ; and I claim that each of these points of view is of equal 

 importance to any one claiming the title of biologist. 



It would be perfectly possible to add to the list : Economic 

 Zoology and Historical Zoology at once occur to the mind. 

 It would be equally possible to arrange for a divergence in 

 specialisation in a student's last year, some choosing the more 

 physico-chemical, some the more biological side of the subject. 

 But such details must depend on the experience gained as 

 teaching adapts itself to the growth of the subject, and also 

 upon local conditions. 



Thus what I had in mind in arranging for this series, was 

 to make an attempt to cover these separate fields, each field 

 being handled on approximately the same scale. Some 

 modern developments have been so well treated in recent years 

 that I have not thought it worth while to enter into useless 

 competition with the admirable existing works. That is 

 eminently the case with genetics, in which the volumes by Crew, 

 Morgan, Jones, and others already carry out what was in my 

 mind. 



Other fields have also been covered, but covered too well. 

 Parker and Haswell, Adam Sedgwick, MacBride's Invertebrate 

 Embryology and Graham Kerr's Vertebrate Embryology, are 

 books of reference. To ask undergraduate students to read 

 through such works is merely to give them mental indigestion, 

 though they may obviously be used with great profit in con- 

 junction with lecture-notes and short text-books. 



T. H. Huxley, that great scholar and man of science whose 

 name I am proud to bear, wrote one text-book of Vertebrate, 

 another of Invertebrate Anatomy. It is text-books of that 

 size and scope at which this series aims, in which the detail 

 shall be used to illustrate the principles, but no deadening 

 attempt made at a completeness which in any case must remain 

 unattainable. 



