PREFACE ix 



British biologists, many of them for long years my personal 

 friends, on the ground that my Croonian Lectures implied that 

 I regard them all as " academic." This, let me hasten to assure 

 them, is very far from being the case. If these lectures be read 

 with reasonable care it will be seen that no such charge is made. 

 I was concerned not to cover the whole ground of modern in- 

 vestigations upon the problems of evolution, but to show the 

 bearing of medical research upon matters pertaining thereto. 

 I realize full well that it would have strengthened my case to 

 refer to the work and views of Walter Heape, Professors E. W. 

 MacBride, A. Dendy, and M. Hartog to mention only those 

 known to me from old association as confirming my earlier 

 conclusions. I realize this after the event more fully than 

 before, when I had in mind others who from their position and 

 reputation have, rightly or wrongly, been regarded popularly 

 as yet more leading representatives of British biology. 



Nor had I in mind American biologists. To have referred 

 to them would have necessitated entrance at length into the 

 Mendelian controversy, for all the morphologists in the States, 

 I am inclined to think, are at the present moment keenly engaged 

 over this matter. Possibly in the future, I shall have a word 

 to say upon the important studies of Castle, Osborne, Whitman, 

 Morgan, Jennings, and others, and the interpretation of the same 

 in the terms of the biophoric concept. In the meantime may 

 I assure my American confreres that I cannot call to mind one 

 of them whom I would accuse of being " academic." On the 

 contrary, never has there been a period when American biologists 

 have manifested so great an individual independence, so notable 

 a diversity of opinion, so pronounced a desire to arrive individu- 

 ally at the truth, irrespective of the schools and their teachings. 



The time indeed has passed when any biologist should justly 

 be labelled as either a Lamarckian or a Darwinian. With 

 abundant material presented to him and freedom of individual 

 judgment, it is scarce possible that the student of to-day should 

 accept unreservedly the teaching of either Lamarck or Darwin. 



