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THE AMEIUCAX A . I TV 11. 1 LIST [Vol. XLIII 



quences of phenomena. Tims the quest for reality along 

 the road of unity lands us in a complete reductio ad ab- 

 surdum, acceptable possibly to some metaphysicians, but 

 utterly repugnant to the clarified common sense of 

 science. 



If this line of thought as to the status of the individual 

 and the species seems unprofitable or pressed too far for 

 the taste of many, let us return to a closely related but 

 more practical consideration which is now a live factor 

 in several working lines of biological science. I refer 

 to the fact that individuals are not units in another sense, 

 —the sense, viz: that they have complex life-histories, 

 and must be so thought of and so spoken of if they are to 

 be treated in a scientific as opposed to a popular sense. 

 An individual animal or plant is not a static but a dynamic 

 thing. It does not all exist at any one time, but exists 

 only as a series or succession of stages, bound together 

 by physical continuity and causation, each preceding stage 

 being an indispensable condition of the next. We can not, 

 thus, by any possibility, handle and ''sort" individuals. 

 We can not even perceive them by a simple perceptive 

 process. All we handle, sort or recognize is specimens; 

 but these, dead or alive, are but fractions of individuals, 

 signs or suggestions of individuals— non-existent at the 

 moment— but which we then proceed to build up in 

 thought by a long process of that same conceptual nature 

 which we use in arriving at our knowledge of species. 



If any one is disposed to gainsay this assertion then 

 let him reply to the question: which, or what, is an indi- 

 vidual insect! Is it the fertilized egg or some embryonic 

 stage, some younger or older larva?— is it the pupa or the 

 imago? Possibly some one may reply, "the imago; this 

 is at least the adult individual, and the only reality neces- 

 sarily considered in dealing with species/' But this is 

 surely an unscientific position to hold at the present time, 

 even with regard to the insect; while, if we shift our at- 

 tention to certain other groups of animals, where growth 

 and to some extent morphological change persist through- 

 out life, even the momentary suggestion of a fixed, stable, 



