u 
REVIEWS. 
the theory of a single centre of distribution, and a common origin for each 
species. 
The desire to write a readable book on a dry subject (an endeavour to 
which, as reviewers, we feelingly say, “ good luck”) has perhaps diverted 
Mr. Wollaston somewhat from the precision and compression of style 
of which he has elsewhere shown himself so capable, and by which he 
might here have done more justice to his own conceptions. There is an 
essay, not a very recent one, by Spring, “ On the ideas of Genus, Species, 
and Variety in Natural History, and the causes of variation in the Organic 
Kingdoms,”* to which we might refer as an example of another mode of 
handling such a subject. We shall only quote from this, however, a few 
sentences, which may help to explain and to remove some obscurities involved 
in many of the speculations about species and varieties, their relation 
and distribution:— 
“ The idea of the species is never fully expressed by'a single individual; it 
can only be exhausted by the aggregate of all the individuals existent in all 
places and times. .... Every discrepancy between individuals is a more 
or less full development of the idea of the species, produced by external in¬ 
fluences ; and the common opinion is erroneous which regards those discre¬ 
pancies (the varieties) as deviations from, and not as contained in, the idea of 
the species. They belong, universally, to the idea of the species, in which 
they are expressed as regards their possible existence. Eor the same reason, 
they are not “ accidental,” as others say; for, given the possibility in the idea 
of the species, then by necessary consequence certain external conditions 
(influences) will produce certain alterations or degrees of development.” 
We have remarked one or two instances of careless style, which might 
have passed unchallenged in the common run of popular essays, but which 
we regret should have slipped from the pen which Mr. Wollaston can wield 
so vigorously and so well. When an insect is characterized as being more 
or “less parallel,” we naturally inquire, “ parallel ” to what? To what 
purpose, again, such a solecism as “ climatal,” and this repeatedly ? 
Does not climatic, or climatical, accurately convey the idea intended, in a 
form agreeable to etymology, and sanctioned by usage ? To the following 
sentence we have failed in our endeavours to affix any suitable and consis¬ 
tent meaning:—“Thus, for instance, the Pissodes notalus Fab., a 
weevil which occurs in pine forests from Lapland to Barbary, and which 
has been naturalized in the Madeira Islands, passes through the alternations 
to which it is specifically subject, irrespective of country.” How is the 
insect specifically subject to alternations, and to alternations of what? 
Irrespective of such minuter criticisms, however, the volume contains a 
large amount of interesting information on the subject in chief, and presents 
some general conclusions which have both originality and apparent evi- 
Fr. Fleischer, Leipzig, 1838. 
