180 
NATURE 
[Fuly 3. 1873 
Oae word more, if men will write nonsense, they might at | should differ from the German professor ; with whom we 
least endeavour to write original nonsense. It is sad t> 
think that even young ladies should have to admire the 
old empty sentences in every new book. S. 
OUR BOOK SHELF 
The Darwinian T. heory and the Law of the Migration 
of Organisms. By Moritz Wagner; translated by J. 
L. Laird. (Sandford.) 
AFTER the perusal of the preface to this pamphlet, the 
reader will expect to find that a serious objection to the 
Dar vinian hypothesis has been detected, and that what 
is to follow will, by the introduction of a ‘new law, clear 
up the assumed difficulty, and immortalise its discoverer. 
“The Law of the Migration of Organisms” of Prof. 
Wagner is that it is only by the isolated migration of 
single individuals from the station of their species, that 
natural selection could and can be effected, and that only 
by this means new varieties of plants and animals could 
arise in the past as well as in the present. This law is 
based on the considerations that the greater the change 
to which individuals are subjected on migration from their 
homes to some fresh locality, the greater will be their 
tendency to vary, and the less they have the opportunity 
of crossing with the parent stock, the more permanent 
will variations become. Most of the observations on 
which these arguments are founded have been arrived at 
from the author’s researches on the distribution of insects 
and plants ; and he has been led to propose it, because, 
as he says, “ Darwin’s work neither satisfactorily explains 
the external cause which gives the first impuls2 to in- 
creased individual variability, and consequently to natural 
selection; nor that condition which, in connection with a 
certain advantage in the struggle for life, renders the new 
characteristic indispensable.” 
To us it is not easy to see what direct bearing this law 
has on the theory of natural selection, for it seems to be 
nothing but one of the many deductions of Lamarck’s 
theory of the origin of species. It is evident that on 
that very ingenious but equally inefficient hypothesis, 
the removal of individuals from their homes to some other 
locality in which the temperature and food are different, 
would cause them to vary ; and that if the so modified 
forms are allowed again to mix with those which have 
not altered their position, the induced peculiarities will 
disappear. But, though by artificial selection an appa- 
rently similar result may be attained, yet in a wild state 
this is hardly the sequence of events which the evolu- 
tion hypothesis supposes. According to it, the forces 
which come into play affect large numbers, and being 
generally comparable in degree and gradual in their 
action, those individuals which escape change in one 
direction are almost certain to undergo some equally con- 
siderable modification in another; consequently there 
will at no time be left any of the original unmodified 
stock for the varieties to intermix with, as required 
in the theory under consideration, at the same time 
that the effect of simple change of locality in producing 
new and well-marked varieties has not been conclusively 
proved. 
From the study of the breeds of horses and cattle, 
Prof. M. Wagner is convinced that the invariable result 
of intercrossing is uniformity, and that only in connection 
with isolation is natural selection able to come into play. 
This, as do many other remarks throughout this pamphlet, 
shows clearly that its author does not really recognise the 
point of Mr. Darwin’s great theory, and that whilst under 
the idea that he is attempting to modify it, he is really 
discussing another, but distantly related, and much less 
important problem. Such being the case, it is not sur- 
prising that the author of the theory of Natural Selection 
also cannot agree in thinking that “perhaps that gene- 
rous British naturalist, who is always open to conviction, 
after calmly weighing his reasons and data, may yet be 
induced to modify his opinions.” 
A Practical Manual of Chemical Analysis ana Assay- 
ing, as applied to the Manufacture of Iron from is 
Ores, and to Cast Iron, Wrought Iron, and Steel as 
found inCommerce. By L. L. de Koninck, Dr, Sc., 
and E. Dietz. Edited, with notes, by Robert Mallet, 
F.R,S., F.G.S., M.LC.E., &c. (London: Chapman 
and Hall, 1872.) 
THE above little work appeared at Litge in 1871, and 
as it was well arranged, succinct, and clear in its descrip- 
tions, Mr. Mallet considered it worthy of translation. The 
plan is similar to that of Fresenius’s well-known quanti- 
tative analysis, the reagents being described first, then 
the apparatus and operations, and then the practical 
application to the special class of work to which the 
book is devoted. On the whole we cannot help 
thinking that too much space is given to matter 
with which every person ought to be thoroughly familiar 
before he attempts to make a practical application of his 
chemical knowledge. The supercession of the skilled 
chemist by the “tolerably intelligent man” mentioned by 
the editor in his preface is not, we think, a desirable re- 
form. The editor’s notes consist of some four and twenty 
pages of small print at the end of the book, and they are 
full of valuable suggestions. His remarks on the con- 
struction and arrangement of the laboratory of an iron- 
work are particularly worthy of attention. The book 
concludes with a table of atomic weights, one for the 
conversion of English weights and measures, with their 
metrical equivalents, and one of constants for calculating 
percentages of substances found. The book will no 
doubt prove very useful in its special field, 
Verhandlungen der k.-k. Zoologisch-botanischen Gesell- 
schaft in Wien. Jahrgang, 1872, 22° Band, (Leipzig 
Brockhaus.) 
THE annual volume of “ Transactions of the Zoological 
and Botanical Society of Vienna” contains, as usual, a 
number of interesting and valuable articles. The papers 
are almost entirely systematic and descriptive :—On the 
flora of Poland (the longest paper in the volume); on 
birds from the shores of China and Japan ; on the lichens 
of the Tyrol ; on a collection of birds from Australia ; on 
the bees of Germany; on North American Micro-Lepi- 
doptera ; on the oak-galls of Central Europe; and others 
of a similar character. Physiological or anatomical con- 
tributions occupy but a small portion of the volume, which 
is illustrated by seven plates. 
The Art of Grafting and Budding. By Charles Baltet. 
(London : W. Robinson, 1873.) 
THE various modes of the reproduction of plants com- 
prised under the designations grafting, budding, layering, 
&c., have been more scientifically studied and carried to 
greater perfection by gardeners in France than in Eng- 
land. Baltet’s “L’Art de Greffer” is the text-book on 
this branch of horticulture, and of this little volume we 
have here a translation, although the omission to note 
this fact on the title-page might give unwary purchasers 
who have not dipped into the preface the impression that 
it is an original work, M. Baltet is so successful a fruit- 
grower, and his manual is so well and favourably known, 
that no apology was necessary in furnishing the English 
reader with a translation of it, which will be an indis- 
pensable companion to all engaged in horticulture. At the 
end of the volume is a useful list of the more commonly 
grown trees and shrubs, with instructions as to the best 
kind of stock on which to graft them, and the method to 
be pursued ; though it is a pity that the translator did not 
