216 
P0PT7LAE SCIENCE EEVIEW. 
mental operations of the Creator at every step.” Mental operations are the 
necessities of an individual who does not possess Omniscience ; they are a 
clumsy method of acquiring truth which are quite inconsistent with a 
sublime conception of a Creator. 
“ Our Reptiles ” is an excellent little work on the frogs, snakes, toads, 
newts, and lizards indigenous to Britain. Mr. Cooke writes in a light and 
pleasing style ; and, when he deals with the zoology of the creatures he has 
undertaken to describe, he tells us much that is both new and true. But 
critics are always cavillers, and so we suppose we must find a little fault with 
some of our author’s observations. For example, although we do not object to 
his describing the true Reptilia and the Amphibia under the one general title 
of Keptiles, we cannot assent to his statement that they have a greater affinity 
with fishes than with birds. Indeed, by placing Amphibia and Reptilia 
together, it is impossible to say that the compound group has a greater 
affinity for birds than for fishes. The piscine early life of the frog, the 
metamorphoses it undergoes, and the absence of an amnios or allantois in the 
embryo all relate it to the fish. On the other hand, the single occipital 
condyle of the lizard, the presence of an amnios in the embryo, the absence 
of gills at all periods of its life, and the absence of metamorphoses, make it 
approach Aves very closely. Mr. Cooke should, therefore, have avoided the 
question of affinity, or he should have separated the Amphibians from the 
Reptiles. Again, he is not strictly correct in saying that, because the heart 
of the reptile has only 11 one ventricle, the result of this is that respiration is 
imperfect.” Respiration is imperfect from several causes : but pre-eminently 
because the air-vesicles are so large that but a small quantity of blood can be 
exposed by them to the air, in a given time. Neither is he accurate in saying 
that “ respiration gives heat to the blood.” He seems, too, to be unaware 
that true reptiles have the ventricles nearly divided into two chambers, and 
that in the crocodile there are two perfect ventricles, and that pure arterial 
blood circulates in the head and upper extremities of this animal. But these 
are trifling matters, when it is remembered that the pretty volume under 
notice is not intended to be a treatise on comparative anatomy, but upon the 
natural history of our British reptiles. Concerning its merits as a popular 
zoological book, we must speak highly of Mr. Cooke’s production ; it is 
concise without being superficial, and is accurate without being technical. 
Eleven handsome coloured plates accompany the text. 
“ British Beetles ” is a book which stands so much upon the boundary-line 
between pure and popular science, that we hardly know to which department 
it really belongs. We have assumed it to belong to the latter, although we 
are not quite sure that we are justified in the assumption. It is a sound 
treatise on our native Coleoptera, but we think it abounds too much in 
technicalities for most general readers. We admit that the glossary of 
terms is full and intelligible, but we do not think that mere beginners will 
like to learn off a few pages of tough dictionary work before commencing 
their practical pursuits. Still, Mr. Rye has done good service to the branch 
of entomology upon which his book treats ; and, even if the tyro fails in 
understanding the technical diagnosis of the text, he cannot fail to identify 
his beetles by the aid of the admirably coloured plates appended to the 
volume. 
