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POPULAR SCIENCE REVIEW. 
it be one of those terms which have in every age trammelled the progress 
of philosophy ; therefore we request that a species be defined by our 
opponent. We have shown that new animal forms , differing as much from 
each other as recognized [species r do, have been called into existence by 
natural and artificial selection, and that is a great step towards the solution 
of the mystery. It is true that these forms are capable of combining 
genetically, but may we not suppose that the varieties, most unlike, may, 
in course of ages, and after subjection to different external conditions, be 
so altered, physiologically as well as morphologically, that their capability 
of fertile inter-communication shall diminish or cease? A chemical 
element is to a certain extent analogous to a species ; it possesses its own 
intrinsic properties, yet if it be submitted to new conditions, it will be so 
materially altered that it will possess several new properties, and will have 
lost some of its former ones. Take phosphorus for example ; what can be 
more remarkable than the power which the red allotropic variety possesses 
of forming compounds with sulphur, which the other kind is devoid of ? We 
might give similar illustrations ad infinitum. One thing is significant ; 
species can have originated in but one of two ways — creation and natural 
selection. A few traditions are evoked in support of the former method ; 
a thousand arguments from analogy support the latter. We do not say 
Mr. Darwin’s doctrine is unquestionably the right one, but we do maintain 
that it is the one most in accordance with recognized facts, and that also 
which appeals above all to our reasoning faculties. 
M. Flourens’ book will afford a certain amount of satisfaction to the 
disciples of the old school, but it will be read by Darwinians with intense 
amusement. 
FORCE AND MATTER.* 
I F the reader were to take up this volume in expectation of finding a 
disquisition upon those beautiful laws enunciated by Grove, Tyndall, 
and others, he would be sadly disappointed. The title does not express 
correctly the nature of the work. Dr. Biichner’s treatise, though dealing 
indirectly with the results of modern scientific research, is incontestably a 
work on Atheism. In every page we find a slashing attack on the Deistic 
creed, and though in many instances the author has conducted his side of 
the controversy with becoming impartiality, in others he has set no bound 
to his opinions, and the expression of his views is characterized by a low 
style of language, which certainly borders on the grossest form of blasphemy. 
Considered apart from these features, the work is an interesting one, and 
may be read with advantage by those who are not easily led away by a 
subtle sophistry. The first object of the writer is to show that matter is 
indestructible, and this he achieves with tolerable success ; but when he 
* i( Force and Matter ; Empirico-Philosophical Studies intelligibly 
rendered.” By Dr. Louts Buchner. Edited from the last edition of 
“ Kraft und Stoff.” By J. F. Collingwood, F.R.S.L., &c. London : 
Tiubner & Co. 1864. * 
