DIFFERENTIATION, MIGRATION, AND MIMICRY. 385 



I have endeavoured to show that there is still room for all 

 workers, that the naturalist has his place, though the morphologist 

 and the physiologist have rightly come into far greater promi- 

 nence, and we need not yet abandon the field-glass and the lens 

 for the microscope and the scalpel. The studies of the labora- 

 tory still leave room for the observations of the field. The inves- 

 tigation of muscles, the analysis of brain tissue, the research into 

 the chemical properties of pigment, have not rendered worthless 

 the study and observation of life and habits. As you cannot 

 diagnose the Red Indian and the Anglo-Saxon by a comparison 

 of their respective skeletons or researches into their muscular 

 structure, but require to know the habits, the language, the modes 

 of thought of each ; so the mammal, the bird, and even the 

 invertebrate, has his character, his voice, his impulses, aye, I will 

 add, his ideas, to be taken into account in order to discriminate 

 him. There is something beyond matter in life, even in its 

 lowest forms. I may quote on this the caution uttered by a pre- 

 decessor of mine in this chair (Professor Milnes Marshall) : 

 11 One thing above all is apparent, that embryologists must not 

 work single-handed ; must not be satisfied with an acquaintance, 

 however exact, with animals from the side of development only ; 

 for embryos have this in common with maps, that too close and 

 too exclusive a study of them is apt to disturb a man's reasoning 

 power." 



The ancient Greek philosopher gives us a threefold division 

 of the intellectual faculties, — <pp6vwi$, ETriaTYiiw, <rvvs<ris — and I think 

 we may apply it to the subdivision of labour in natural science : 

 $povYi<ri$ y yi rot Y.a8 sxoHTTa yvcopiZouaa, is the power that divides, dis- 

 cerns, distinguishes — i. e. } the naturalist ; fuvEmr, the operation of 

 the closet zoologist, who investigates and experiments ; and 

 e7ri<7TYiiA,y, the faculty of the philosopher, who draws his conclusions 

 from facts and observations. 



The older naturalists lost much from lack of the records of 

 previous observations ; their difficulties were not ours, but they 

 went to Nature for their teachings rather than to books. Now 

 we find it hard to avoid being smothered with the literature on 

 the subject, and being choked with the dust of libraries. The 

 danger against which Professor Marshall warns the embryologist 

 is not confined to him alone ; the observer of facts is equally 

 exposed to it, and he must beware of the danger^ else he may 



