REVIEWS. 
503 
approaches his second aim, we think he loses himself in a muddle of 
metaphysics. In trying to puove that force has always existed, we find he 
has placed the reader in the same position with regard to himself, as that 
alluded to in the Scotchman’s definition of the science of mind, — for assuredly 
“ he dinna ken exactly what he means,” and his reader “doesn’t under- 
stand him.” In this respect we think Dr. Buchner has gone a step too far. 
So long as he exerts his reasoning powers, we shall be anxious to listen to 
him, but when he travels beyond his proper sphere, and asserts that because 
“ all the planets of our system are not so formed as to be inhabited by man,” 
there is therefore no God, wo shall most unquestionably refuse to argue 
with him. In making such an assertion he passes from what he can com- 
prehend to what he cannot, and thus his whole argument is founded on a 
petitio principii . 
BRITISH CONCHOLOGY.* 
W HEN noticing the first volume of Mr. Jeffreys’ work, we had 
occasion to speak in very complimentary terms of its character 
as a text-book for the student and a readable companion for the amateur. 
The second volume is now before us, and we observe nothing in it calculated 
to alter the opinion we before expressed. That portion of the “ British 
Conchology ” which deals with marine shells, is as well executed as the 
rest, and contains, besides a most interesting “ introduction,” the Zoology 
of the Brachiopoda, and of the Lamelli branchiata from the family of the 
Anomias to that of the Mactras. The author’s style is peculiarly felicitous, 
and is attractive even to those who know nothing whatever of natural 
science. It must not be supposed, on that account, that accuracy has been 
made subservient to popularity ; far from it ; we observe, on the contrary, 
that the most recent researches find a notice, and that on certain points 
where doubt is justifiable, a fair proportion of scepticism is exhibited. 
Selecting the genus Ostreea as a type of what Mr. Jeffreys has done for 
our British shells, we perceive, first, a description of the genus, then a list 
of the specific synonyms and description of the species, which is of con- 
siderable length ; next follow the several varieties, and finally we arrive 
at the natural history of the mollusk. This is the pleasantest reading of 
all ; there are nine pages of letter-press devoted to the habits, distribution, 
structure, commercial bearings, culture, and history of the oyster, and these 
our readers should certainly make themselves familiar with. If we were 
to be exceedingly critical, we should say that the geographical distribution 
is not as amply given as it might have been, but in other respects the book 
is a most valuable one, and possesses in combination a greater number of 
good qualities than we usually find united in treatises of its class. 
* “ British Conchology ; or, an Account of the Mollusca which now 
inhabit the British Isles and the surrounding Seas.” Yol. II. Marine 
Shells. By J. Gwin Jeffreys, F.R.S., F.G.S., &c. London : Van Voorst. 
1863. 
