408 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1915. 



spective of past and present in our study of the problems of animal 

 life. The destructive phase through which we have passed has thor- 

 oughly cleared the ground for the new constructive era on which we 

 now have entered. All the signs of the times indicate that this era will 

 long endure. And this is of good augury for a future of productive 

 effort, guided by the methods of physico-chemical science, impatient 

 of merely a priori constructions, of academic discussions, of hy- 

 potheses that can not be brought to the test of experimental verifica- 

 tion. The work ahead will make exacting technical demands upon 

 us. The pioneer days of zoology are past. The naturalist of the 

 future must be thoroughly trained in the methods and results of 

 chemistry and physics. He must prepare himself for a life of inten- 

 sive research, of high specialization ; but in the future, even more 

 than in the past, he will wander in vain amid the dry sands of special 

 detail if the larger problems and general aims of his science be not 

 held steadfastly in view. For these are the outstanding beacon lights 

 of progress; and while science viewed at close range seems always to 

 grow more complex, a wider vision shows that her signal discoveries 

 are often singularly simple. This, perhaps, may help us to keep alive 

 the spirit of the pioneers who led the advances of a simpler age, and 

 it is full of hope for the future. 



