I4<S Allen, Gdtke's 'Heligoland: [^, 



night it is impossible for them to distinguish the nature of the 

 country beneath them, and that hence if they were possessed 

 of a highly developed local sense of direction it would be of no 

 service to them on such journeys. 



In regard to the ''immediate cause of the departure of birds 

 on their migrations." he believes "we are confronted with a 

 riddle which has hitherto defied every attempt at a solution, 

 and which indeed we may hardly expect will ever be likely to 

 receive a final explanation. ... In thus abstaining from setting 

 forth new theories, I have been guided by the conviction, ren- 

 dered firmer with increasing knowledge of the phenomena, that 

 what at present has been ascertained in reference to the migra- 

 tion of birds furnishes us with no clue, by the aid of which we 

 are enabled to penetrate the depths of this wondrous mystery" 

 (p. .48). 



In reality, great light has unquestionably been thrown upon 

 the causes of migration, the manner of its performance, the con- 

 ditions which influence it, and the factors that aid in guiding 

 birds on their migrations, by the systematic observations so 

 extensively carried on in Fairope and in America, during espe- 

 cially the last ten or twelve years. Yet the love of mystery is 

 so inherent in the popular mind, and the habit of viewing the 

 migration of birds as the " mystery of mysteries " in bird life is 

 so firmly fixed, that it is perhaps not strange that a reasonable 

 explanation of all the principal phenomena of the subject should 

 be received as unwelcome iconoclasm on the part of one who 

 clings tenaciously to life-long modes of thought. The "several 

 very ingenious and plausible hypotheses," resulting from " long 

 and profound study," find no favor with Herr Giitke, though 

 favorably received by the newer school of migration observers, 

 who consider the subject as no longer invested in "impenetrable 

 mystery." 



In Part II (pp. 151-164) he takes up the subject of * Changes 

 in the Colour of the Plumage of Birds without Moulting,' in the 

 discussion of which the author displays a depth of ignorance and 

 a misapprehension of simple facts that ill comports with his claim 

 of "having for many years devoted the most unremitting atten- 

 tion " to the subject. He evidently knows little about the way birds 



