SCIENCE 



[N. S. Vol. XLI. No. 1044 



we do not always succeed in keeping them 

 clear of metaphysics, but at least we have 

 learned to try. "VVe perceive more and more 

 clearly that science does not deal with xilti- 

 mate problems or with final solutions. In 

 order to live science must move. She at- 

 tempts no more than to win successive 

 points of vantage which may serve, one 

 after another, as stepping stones to further 

 progress. When these have played their 

 part they are often left behind as the gen- 

 eral advance proceeds. 



In respect to the practical applications of 

 science we have almost ceased to wonder at 

 incredible prodigies of achievement ; yet in 

 some directions they retain a hold on our 

 imagination that daily familiarity can not 

 shake. Not 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 welfare ; and here in less direct ways 

 she plays a part in the advance of our civil- 

 ization that would have been inconceivable 

 to our fathers. Popular writers delight to 

 portray the naturalist as a kind of reani- 

 mated antediluvian, wandering aimlessly 

 in a modem 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 natu- 

 ralist a dream that the construction of the 

 Panama Canal would turn upon our ac- 

 quaintance with the natural history of the 

 mosquito, or that the health and happiness 

 of nations — nay, their advance in science, 

 letters, and the arts — might depend meas- 

 urably on the cultivation of our intimacy 

 with the family lives of house-flies, fleas 

 and creatures of still more dubious ante- 

 cedents ! 



I 



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 rapidlj'- 

 gathering headway in zoology. To-night 

 I once more ask attention to this subject as 

 viewed in the fuller light of the remark- 

 able period of progress through which biol- 

 ogy has since been passing. I will not try 

 to range over the whole vast field of zool- 

 ogy or to catalogue its specific advances. 

 I will only permit myself a few rather 

 desultory reflections suggested by a retro- 

 spect upon the progress of the past 

 twenty-five years. If my view is Jiot 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 be- 

 tween zoology and botany, for instance, 

 has lost all significance for such sub.jects 

 as genetics or cytology. Again, the arti- 

 ficial boundary often set up between zoology 

 and animal physiology has wholly disap- 

 peared, owing to the extension of experi- 

 mental 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 in- 

 quiry may be embodied in two questions: 

 What is the living organism, and how has 

 it come to be ? We often find it convenient 

 to lay the emphasis on one or the other of 

 these questions, but fundamentally they 

 are inseparable. The existing animal bears 



2 Science, N. S., XIII., No. 314, January 4, 



