345 
ItEYIEWS. 
WARM-BLOODED VERTEBRATES * 
A FAR shorter interval elapsed between the publication of the first and 
second parts of the present series of Professor Owen’s work than we 
had been led to anticipate. In our last Number we noticed, at some length, 
the first volume of the “Anatomy of Vertebrates,” and we now proceed to dis- 
cuss the merits of the concluding division of this fine treatise. When treating 
of Professor Owen’s transcendental speculations, we could not conscientiously 
award them that praise which we freely accord to his labours in the field of 
anatomy. There is, in all instances, a great distinction to be drawn between the 
facts which an author lays before his readers and the inferences which he draws 
from them. And although most people are careless as to this distinction, it 
is one of considerable importance, and of an importance which is especially 
illustrated in the case of the writer of the work under notice. If we separate 
the facts from the fancies of the present volume — and the separation is by 
no means difficult, — we arrive at a proper method of estimating the author’s 
worth. Professor Owen stands forward prominently as a naturalist of the 
“ Conceptive ” school ; he therefore advocates doctrines of homology and 
harmony which, while they are extremely fascinating and full of poetic beauty, 
are not the expression of honest generalization. But when we turn from his 
hypotheses and survey the vast accumulation of anatomical facts which the 
devotion of a lifetime to. Natural Science has produced, we can then see 
how much we are indebted to Professor Owen for a comprehensive knowledge 
of the structure of animals. In the exploration of the animal frame our 
author has not been surpassed by his great predecessors, Hunter or Cuvier, 
though in regard to his theoretical speculations he has travelled much further, 
and, we may say, “ fared worse ” than either of them. 
Our readers will remember, from our notice of vol. I., that Professor Owen 
divides V ertebrates into two great natural groups , — Hcematocrya and Hcema- 
totherma, which correspond respectively to the popular terms cold-blooded 
and warm-blooded. The first volume dealt exclusively with the former 
section ; the present one treats entirely of the latter. The classification of 
birds does not materially differ from that already in vogue among zoologists, 
except that it is proposed to embrace a division of the class into two groups, 
in accordance with the characters which the young present when they emerge 
from the shell. This binary mode of arrangement was originally suggested 
* “ The Anatomy of Vertebrates,” vol. II. Birds and Mammals. By 
Richard Owen, F.R.S. London : Longmans & Co. 1866. 
