398 THE POPULAR SCIENCE MONTHLY 



Darwin's extreme desire to perfect his work that allowed me to come 

 in, as a very bad second, in the truly Olympian race in which all philo- 

 sophical biologists, from Bnffon and Erasmus Darwin to Eichard Owen 

 find Robert Chambers, were more or less actively engaged. 



And this brings me to the very interesting question: Why did so 

 many of the greatest intellects fail, while Darwin and myself hit upon 

 tlie solution of this problem- — a solution which this celebration proves 

 to have been (and still to be) a satisfying one to a large number of 

 those best able to form a judgment on its merits? As I have found 

 what seems to me a good and precise answer to this question, and one 

 which is of some psychological interest, I will, with your permission, 

 briefly state what it is. 



On a careful consideration, we find a curious series of correspon- 

 dences, both in mind and in environment, which led Darwin and myself, 

 alone among our contemporaries, to reach identically the same theory. 



First (and most important, as I believe), in early life both Darwin 

 and myself became ardent beetle-hunters. Now there is certainly no 

 group of organisms that so impresses the collector by the almost infinite 

 number of its specific forms, the endless modifications of structure, 

 shape, color and surface-markings that distinguish them from each 

 other, and their innumerable adaptations to diverse environments. 

 These interesting features are exhibited almost as strikingly in tem- 

 perature as in tropical regions, our own comparatively limited island- 

 fauna possessing more than 3,000 species of this one order of insects. 



Again, both Darwin and myself had, what he terms " the mere pas- 

 sion of collecting,"- — ^not that of studying the minutiae of structure 

 either internal or external. I should describe it rather as an intense 

 interest in the mere variety of living things-^the variety that catches 

 the eye of the observer even among those which are very much alike, 

 but which are soon found to differ in several distinct characters. 



Now it is this superficial and almost child-like interest in the out- 

 ward forms of living things, which, though often despised as unscien- 

 tific, happened to be the only one which would lead us towards a solu- 

 tion of the problem of species. For nature herself distinguishes her 

 species by just such characters — often exclusively so, always in some 

 degree — very small changes in outline, or in the proportions of appen- 

 dages, as give a quite distinct and recognizable fades to each, often 

 aided by slight peculiarities in motions or habits ; while in a large 

 number of cases differences of surface-texture, of color, or in the details 

 of the same general scheme of color-pattern or of shading, give an 

 unmistakable individuality to closely allied species. 



It is the constant search for and detection of these often unexpected 

 differences between very similar creatures, that gives such an intellec- 

 tual charm and fascination to the mere collection of these insects; and 



