REVIEWS. 
297 
NATURAL SELECTION.* 
M R. WALLACE, to whom science is nearly as mucli indebted for the 
theory of Natural Selection as it is to Mr. Darwin, has done wisely 
and well to reprint, in the convenient form of a volume, the more important 
of those scientific papers in which from time to time he advocated and 
supported the now generally accepted doctrine of the origin of species. It 
will be unnecessary for us to enter critically into Mr. Wallace’s chapters, as 
the several articles have already been for years before the public, and have 
been dealt with by both scientific and general reviewers. We would, how- 
ever, refer to one of them as of surpassing interest, for in it the author 
attempts an intensely difficult problem in trying to apply the general 
evolutional doctrine to the phenomena which are popularly included under 
the term instinct. The remarks in this chapter have not hitherto been 
published. The author’s definition of instinct seems to us to be especially 
a good one, and to be sufficiently comprehensive to include all the 
operations which properly come within the term. Mr. Wallace says that 
instinct is “the performance by an animal of complex acts absolutely 
without instruction or previously acquired knowledge.” This is perfectly 
satisfactory, and though it does not seem to us that in the present state of 
science Mr. Wallace is in a position to explain the more curious examples of 
instinctive acts, he has certainly gone far towards convincing us that 
instinct is not to be explained by any reference to a supernatural law. His 
remarks on the questions, “Does man possess instinct?” and “How 
Indians travel through unknown and trackless forests,” are admirable 
examples of candour in acknowledging difficulties, and of clear reasoning 
on the facts as we know them. Mr. Wallace’s book is one which is 
intelligible to an ordinarily clear-headed person, and it is of course a 
standard book which every biologist must have on his bookshelves. The 
following is a list of the chapters it contains, with the dates of their first 
publication : — 11 On the Law which has regulated the Introduction of New 
Species ” (September 1855) ; “ On the Tendency of Varieties to depart 
indefinitely from the Original Type ” (August 1858) ; “ Mimicry and other 
Imitative Resemblances among Animals” (July 1867); “The Malayan 
Papilionidse, or Swallow-Tailed Butterflies, as Illustrations of the Theory of 
Natural Selection ” (March 1864) ; “ On Instinct in Man and Animals ” 
(not before published) ; “ The Philosophy of Birds’ Nests ” (July 1867) ; “ A 
Theory of Birds’ Nests ” (1868) ; “ Creation by Law ” (October 1867) ; “ The 
Development of Human Races under the Law of Natural Selection ” (May 
1864) ; and, lastly, “ The Limits of Natural Selection as applied to Man.” 
THE INTERIOR OF THE EARTH.f 
T HE reader of this work will do well, in the first instance, to understand 
clearly that the author is not the eminent authority on earthquakes 
and volcanic action, but is an outsider in science, who, from a few imperfect 
* “ Contributions to the Theory of Natural Selection : a Series of Essays.” 
By Alfred Russel Wallace. London : Macmillan, 1870. 
t “'The Interior of the Earth.” By II. P. Malet, E.I.C.S. London: 
H odder & Stoughton, 1870. 
