298 Dr. J. H. Blasius on the Diversity in the Estimate 
branches of zoology. The spirit of Linne, Pallas, and Cuvier 
ruled the entire domain of zoology. As soon as ornithology 
hastened forward with more rapid strides, it began to emancipate 
itself from other branches of zoology, and struck, as regards 
the conception of species, into a totally different course. The 
majority of ornithologists of note troubled themselves but little, 
or not at all, with other departments of zoology; they found no 
check upon their efforts in the stricter conception of the other 
classes of animals; their conception of species became constantly 
more and more isolated and, in course of time, looser and less care¬ 
ful in comparison with the prevailing zoological procedure. 
For a long time Brehm was the only ornithologist who fol¬ 
lowed this bolder conception as a matter of principle. Towards 
the close of the year 1840, Bonaparte also gradually acquired 
the same taste; but he never went so far as that he could have 
formed a bridge between Brehm and the other ornithologists. 
In his fundamental views he entirely belonged to the opposite 
school in ornithology, and vacillated only as to the signification of 
some local races differing in colour, but similar in form. Gloger, 
Schlegel, and Thienemann still endeavoured to maintain the old 
classical zoological point of view. 
If we examine the ornithological species-question from this 
zoological point of view, the gap between the two extreme 
schools becomes still more distinctly marked. Of the above- 
mentioned 60 doubtful forms, which are regarded by most zoo¬ 
logists as varieties, by many ornithologists at different times as 
species, about 50 would decidedly have to be united with the 
allied forms. Scarcely ten of these forms would remain as still 
fluctuating zoologically. According to the views which have 
hitherto been followed practically by Schlegel, Gloger, and 
Thienemann, to which I may add my own, the European Ornis 
would consist of about 425 certain species, 10 doubtful forms, 
and 100 exotic immigrants. 
On the other hand, Brehm, in his “ Vogelfang,” cites, besides 
these 420 certain species, 520 others, of which the boldest orni¬ 
thologists of the opposite party mention 60 at the outside, and 
besides these again, nearly 1400 subspecies. The number of 
species not certainly well founded with Brehm is fifty times, 
