336 Bibliographical Notice. 



risks of being broken whenever the bird entered the nest, while 

 white eggs, in this dim religious light, are just visible." 



One of the many interesting suggestions in the chapter on the 

 care of offspring concerns the bright colours which are sometimes 

 seen around and in the mouth of nestlings ; these are interpreted 

 as guides to the parents when feeding their young ; but this is only 

 one of the many fresh pieces of biological interpretation in this 

 section of the book — where, indeed, to our thinking, the high-water 

 mark is reached. In the last of the chapters in this section the 

 author deals with the periods of life and their expression in the 

 plumage, and ends up with death, in regard to which we are glad 

 to have from a naturalist with so wide an experience of birds a 

 confirmation of an important generalization. He says " death from 

 senescence is probably rare indeed." By a momentary lapse of 

 artistic sense, or for some reason the true inwardness of which is 

 too subtle for our perception, the author passes beyond the full stop 

 of death to offer a few notes on play, which suggest, moreover, an 

 insufficient appreciation of the work of Groos. 



There are so many points of interest in the section dealing with 

 variation and heredity, selection and isolation, that we are em- 

 barrassed in our attempt to select what is most distinctive. We 

 may refer, however, to what is said of discontinuous variation ; to 

 the suggestion (that recalls Weismann) of variations going on in- 

 creasing in a given direction if selection does not stop them ; to the 

 cautiously expressed idea of the environment supplying variational 

 stimuli — an idea which will perhaps bulk largely in the future of 

 aetiology ; to the rejection of the view that modifications may be 

 transmissible ; to the interesting paradox that the displaying of 

 plumage is a habit very much more ancient than having gorgeous 

 plumage to display. It is characteristic of the book throughout 

 that it opens many doors of inquiry and closes next to none ; it does 

 not " finish " subjects, but suggests what must be done to develop 

 them. Thus it is natural that it should end by bringing the reader 

 back to the facts of adaptation which are before us as riddles still 

 imperfectly read ; and one of the remarkable facts about adaptation 

 is that with which the book closes, that the same kind of result 

 may be reached along different paths by animals which are not 

 nearly related to one another. 



In his illustration of the chief concepts of the evolution theory 

 Mr. Pycraft calls attention to the mass of material that has passed 

 through the hands of ornithologists without being fully utilized, and 

 to the numerous opportunities for crucial observations and experi- 

 ments that have been lost. But this was inevitable with the rapidly 

 widening Darwinian outlook, and it serves little purpose to reproach 

 the past. Mr. Pycraft has done much better than that, for he has 

 produced a book which will be an inspiration to many an ornitho- 

 logist with the root of the matter in him who has been working 

 along rather narrow lines. He has given us one of the most inter- 

 esting and educative books that we have read for many a day, and 

 he has our hearty thanks and congratulations. 



