558 SCIENCE PROGRESS. 



those who are contemplating systematic investigation of the 

 problem of species should begin by the study of such cases 

 as these. It is, in short, reasonable that the study of varia- 

 tion should be begun with the systematic study of varieties. 



By disregard of this limitation a greater scope for 

 statistical refinement may be rendered possible — for the 

 observer is thus free to choose the subject most amenable 

 to such treatment — but it may be questioned whether the 

 compensation is adequate, and whether the solution of the 

 particular problem of the nature and origin of specific dif- 

 ferences is greatly promoted thereby. 



With this limitation, however, begins a real difficulty, 

 one that it must be feared will for long beset the serious 

 study of evolution. In order even to choose subjects for 

 his inquiry, still more in order to pursue them, the student of 

 evolution needs the peculiar knowledge and experience — the 

 whole apparatus, in fact, — which only the collector possesses. 

 In all this he is too often deficient. It is much if the very 

 names of common objects of natural history are familiar 

 to him, and the world of " good species " and " bad species " 

 is unknown. Seldom even can the two classes of men greatly 

 help each other. The collector finds the evolutionist igno- 

 rant of what he regards as the rudiments ; he only vaguely 

 perceives the other's purposes and is not greatly interested 

 in them. His collection was made with different objects 

 altogether, and though with the best will in the world he 

 puts it at the service of any one who will work at it, he 

 cannot make it serve a purpose for which it was not designed. 

 The other leaves disappointed. His questions are mostly 

 unanswered, and he is tempted to feel that the methods of 

 the collector are narrow and that he has missed his oppor- 

 tunities. Now both men are right. The future is with the 

 evolutionist, but it is the collector who has made it possible 

 for him to begin his work. 



The time has surely come for some attempt at closer 

 collaboration between these two classes of students. Col- 

 lecting in the ordinary sense, amassing once more the 

 specimens of each species and variety in thoroughly familiar 

 ground, such as England and Central Europe, is a well- 



