of Naumann's 'Vogel Deutschlands/ 53 



So much then for the question of the Great Northern Falcons. 

 We have carefully avoided the use of the word " species '' in 

 treating of these forms or races, the characters of two of which 

 are truly enough stated by Mr. Hancock to be " permanent and 

 sharply defined, never blending into each other,'^ while those of 

 the third, though much less marked, and accordingly less easily 

 distinguished, are, we are told by Professor Schlegel, always 

 recognizable. Whatever theories we may hold as to the existence 

 of species in nature, and as to what constitutes them, in practice 

 it must, for the present, we imagine, be left for naturalists to re- 

 ceive or reject them according to their own private judgment. 

 But at the same time, where constant difi"erences, however small, 

 can be observed between particular groups of organic forms, we 

 maintain that these constant differences are worthy of observa- 

 tion, however variable be the value assigned to them as specific 

 characteristics. Accordingly we consider that those who neglect 

 to observe them are rather impeding than advancing the pro- 

 gress of natural history, and are not fulfilling the duties which 

 belong to them as natural philosophers. This last, be it remem- 

 bered, is really a matter of no small importance, since the popu- 

 lar estimate of a science like natural history, whose results are 

 comparatively barren in utilitarian application, is always propor- 

 tionate to the opinion formed of its students' abilities. To 

 guard, however, against misapprehension, we must say that this 

 charge cannot be laid to the authors of the volume under review. 

 They, in nearly all cases, show their readiness to give due con- 

 sideration to such differences as we have spoken of, though, as 

 in the instance which has provoked these lengthy remarks, we 

 believe them to be mistaken in the views they have adopted. 



There is but one other point on which we will detain our readers, 

 and that also is of importance with reference to a rare and in- 

 teresting European species, the synonymy of which Dr. Cabanis 

 has the credit of first reducing to order (Journ. f. Orn. 1853, 

 pp. 81-96). To his paper, and to the account given in the work 

 we are noticing (pp. 74-77), we would refer those ornithologists 

 who are anxious to become acquainted with the whole story. 

 Here we will but glance at its principal features. About 1837 

 Mr. Gould (Birds of Europe, pt. xii. pi. 149) gave, from a single 



