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POPULAR SCIENCE REVIEW. 
(plant and animal) are constantly tlirowing off minute atoms, which, under 
favourable circumstances, are capable of reproducing the particular tissue 
from which they were derived. These accumulate in the ovum on the one 
.side and zoosperm on the other, and in the union of these two the elements 
of the tissues and organs of two individuals combine. Accordingly, there- 
fore, as one or other of these elements predominates, the resultant will 
resemble either the male or female parent. But it sometimes happens that 
the two antagonise each other j and, when this occurs, a certain number of 
the molecules of the early ancestors, which have lain dormant like so many 
^^statoblasts,” come into play and produce reversion. Such is, in rough 
und imperfect outline, the last theory which Mr. Darwin propounds. It is not 
only fully m accord with his theory of natural selection, and with the facts 
which he advances in support of it, but it requires no extreme elasticity of 
imagination for its acceptance j and it is so thoroughly in agreement with 
ordinary physical laws and with the phenomena of development, that we 
think it is likely to find warm advocates in the biologists of all countries. 
Ere we conclude, let us offer our hearty thanks to Mr. Darwin for the 
dignified and truly philosophic manner in which he has conducted his con- 
troversy with his opponents. He has done good to those who have despite- 
fully used him, by showing them that he is uninfluenced by the petty 
feelings which have led them into an indulgence of invective damaging- 
only to their cause. By proving to them that philosophy is beyond vitu- 
peration, he has upheld the honour of science, and cast a silent reproach on 
those who think that credulity and poetic sentiment are higher gifts than 
veason and observation. 
THE STONE AGE.* 
S IB JOHN LUBBOCK has done good service to Ethnology in bringing 
Professor Nilsson’s treatise under the notice of the English public. 
Professor Nilsson, though well known to German Archaeologists, and 
though himself a keen student of British antiquities, has not up to this 
Teceived the recognition of English students. In the volume before us he 
has treated of the relics of the men of the Stone Age in Sweden, and he has 
dealt with his subject in a manner at once so comprehensive and attractive, 
that his work will be read with as much pleasure and advantage by the 
professional as by the amateur Archaeologist. In order to render the book 
as useful as possible even to those unconversant with the recent labours of 
Ethnologists and Geologists, the editor has added an Introduction, which in 
clearness and force of argument is unsurpassed by anything he has before 
written. Sir John Lubbock gives a most instructive sketch of the position 
of prehistoric Ethnology as it stands at present 5 and as his views embrace the 
most modern conclusions, we cannot refrain from giving our readers a brief 
* ^^The Primitive Inhabitants of Scandinavia.” By Sven Nilsson. 
Third edition. Edited, with an Introduction, by Sir John Lubbock, Bart., 
E.B.S. London, Longmans. 1868. 
