1911 J Barbour and Phillips, Concealing Coloration Again. 187 



one dogmatic assertion. For we are asked to believe that an animal 

 is protectively clothed whether he is like his surroundings, or 

 whether he is very unlike them (obliteratively marked); or, on 

 the other hand, if he falls between these two classes, there is still 

 plenty of space to receive him. 



We cannot always presuppose so intense and bitter a struggle 

 among all forms of life that an extremely slight favorable varia- 

 tion turns the balance, or that the constantly recurring momen- 

 tary crises safely passed by the instant action of some color feature 

 preserves one breeding individual in preference to another. The 

 struggle exists, but is it quite so bitter as we would seem to have 

 to believe? We are inclined to temper it with the spirit of altruism 

 which Hanseman has so well discussed in his book, ' Heredity and 

 Pathology.' Here the word altruism is used in a strictly biologi- 

 cal sense as "the reciprocal relation between individuals and be- 

 tween species for the purpose of producing a more favorable modus 

 vivendi for all"; and the idea is developed that annihilation can- 

 not have been the underlying principle of evolution. Indeed, we 

 think that nature is not always bitter. It is hard to find instances 

 of a predatory animal surrounded by its normal environment caus- 

 ing the extinction of any species on which it lives. We do not 

 believe this condition of affairs to be due to protective coloration, 

 either. 



We owe Mr. Thayer a debt of gratitude. He has brought a 

 fascinating subject to a prominence that it has long deserved, but 

 which it has not had. Much of what he shows us, where his illus- 

 trations are applicable to natural conditions, and where they are 

 not specially arranged to illustrate some supposed state of affairs 

 which may be capable at least of double interpretation, are of 

 great value. We do not wish to seem destructive, and we have 

 purposely omitted calling special attention to the strong features 

 of the book. This has been done, and well done, by more able 

 reviewers than ourselves. We have chanced to have, one or the 

 other of us, opportunities for observation in the field in almost 

 every part of the world; and for this reason, if for no other, we 

 have felt emboldened to offer these critical notes; and we can but 

 hope that Mr. Thayer and his followers will read them and inter- 

 pret them in the spirit in which they are written. They are simply 



