396 ANNUAL EEPOET SMITHSONIAN INSTITUTION^ 1915. 



directions they retain a hold on our imagination that daily familiar- 

 ity can not shake. Xot in our time, at least, will the magnificent 

 conquests of sanitary science and experimental medicine sink to the 

 level of the commonplace. Science here renders her most direct and 

 personal service to human Aveliare ; and here in less direct ways she 

 plays a part in the advance of our civilization that would have been 

 inconceivable to our fathers. Popular writers delight to portray the 

 naturalist as a kind of reanimated antediluvian, wandering aimlessly 

 in a modern world where he plays the part of a harmless visionary ; 

 but what master of romance would have had the ingenuity to put into 

 the head of his mythical naturalist a dream that the construction of 

 the Panama Canal Avould turn upon our acquaintance with the natu- 

 ral history of the mosquito, or that the health and happiness of 

 nations — ^nay, their advance in science, letters, and the arts — ^might 

 depend measurably on the cultivation of our intimacy with the fam- 

 ily lives of house flies, fleas, and creatures of still more dubious ante- 

 cedants. 



Fourteen years ago to-night it was my privilege to deliver an 

 address before the American Society of Naturalists, entitled "Aims 

 and Methods of Study in Natural History,"^ in which I indicated 

 certain important changes that were then rapidly gathering head- 

 way in zoology. To-night I once more ask attention to this subject 

 as viewed in the fuller light of the remarkable period of progress 

 through which biology has since been passing. I will not try to 

 range over the whole vast field of zoology' or to catalogue its specific 

 advances. I will only permit myself a few rather desultory reflec- 

 tions suggested by a retrospect upon the progress of the past 25 

 years. If my view is not fully rounded, if it is colored by a long 

 standing habit of looking at biological phenomena through the eyes 

 of an embryologist, I will make no apology for what I am not able 

 to avoid. Let me remind you also at how many points the boundaries 

 between this and other branches of biology have become obliterated. 

 The traditional separation between zoology and botany, for instance, 

 has lost all significance for such subjects as genetics or cytology. 

 Again, the artificial boundary often set up between zoology and ani- 

 mal physiology has wholly disappeared, owing to the extension of 

 experimental methods to morphology and of comparative methods 

 to physiology. I trust therefore that our brethren in botany and 

 physiology— perhaps I should include also those in psychology- 

 will not take it amiss if I include them with us under the good, old- 

 fashioned name of naturalists. 



The sum and substance of biological inquiry may be embodied in 

 two questions: ^Yhat is the living organism, and how has it come to 



1 Science, N. S., vol. 13, no. 314, Jan. 4, 1901. 



