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POPULAR SCIENCE REVIEW. 
closing of fossils in peat, blown sand, and volcanic ejections. The reader 
may readily perceive that within this list of headings is included, if not all, 
at least the great proportion of those subjects which are at the present 
moment of the very highest interest to men w r ho have even the slightest 
consideration for the great secrets and truths of science. It is clear that, 
even if we confined our attention to the more distinctly novel portions of 
the volume, we should far exceed the limits of our reviewing chapter. To 
deal even briefly with them would be more than we can do. We shall, 
therefore, just give the headings of the absolutely new additions to the volume 
under notice, and afterwards we shall treat of one or two subjects which 
appear to us to merit our special attention. The peculiar novelties of this 
portion of the work are the following: the New Zealand geysers, and 
reference to Dr. Tyndall’s illustration of the probable mode of geyser-action ; 
Mr. Scrope, on the action of water in volcanoes; Sir John Herschel and 
Mr. Babbage, on transfer of sediment causing the shifting of the subter- 
ranean isothermals; Mr. Wallace, on the single origin of the dog; Mr. 
Darwin, on sexual selection ; the Rev. R. T. Lowe, on the arrival of a 
flight of locusts in Madeira ; Mr. Darwin, on some cases of abnormal struc- 
ture in prehistoric man corresponding to the structure of the same parts in 
some lower groups of animals; Mr. Mivart’s objections to the theory of 
natural selection, and Mr. Darwin’s reply ; temperature and fauna of Lake 
Superior ; and, finally, the depth to which the ocean is inhabited, as illus- 
trated by deep sea-dredgings, and the amount of difference of the oceanic 
fauna in adjoining warm and cold areas. Now, the matter entirely new 
that is introduced under these successive heads is very extensive. We 
shall, therefore, confine our attention to one or two of the recent points. 
And firstly, of the dog, as to whether he comes from several different pro- 
genitors or from one single animal, the wolf. Sir Charles Lyell says, that 
in regard to the origin of the various canine races which have been domes- 
ticated by man in all parts of the world, there is still no small diversity of 
opinion. Mr. Darwin, after an analysis of all that has been written on the 
subject, inclines to Pallas’s belief, that the dog has a multiple origin ; for 
example, that more than one species has been blended together to produce 
our present distinct races. John Hunter contended that dog, wolf, and 
jackall were all one species, because he had found that the dog would 
breed with the wolf and jackall, and that the mule in each case would breed 
with the dog. u In these cases, however,” says Sir Charles Lyell, u it may 
be observed that there was always one parent at least of pure breed, and no 
proof was obtained that a true hybrid race would be perpetuated.” “ The 
main argument in favour of different breeds of dogs being the descendants of 
distinct wild stocks is their resemblance,” says Mr. Darwin, “ in various 
countries to indigenous species still existing there. For instance, the 
domestic dogs of the American Indians resemble North American wolves ; 
the shepherd dog of Hungary is extremely like the European wolf ; the 
domestic dog of Asia resembles the jackall.” But Mr. Wallace has sug- 
gested to Sir C. Lyell that evidence of this nature loses much of its weight 
when we take into consideration some cases of modification given by him 
and Mr. Darwin, and cited by Mr. Mivart in his “ Genesis of Species.” 
Many distinct species of butterflies are shown to be similarly modified in 
