ae) 
NATORE 
[APRIL 4, 1907 
is included, concerning every substance discussed. 
This first volume deals with the solid elements, with 
the inorganic compounds of a non-saline character, 
such as oxides, sulphides, and phosphides, and with 
the halogen salts, cyanides and salts of the recently 
discovered nitrogen acids. The second volume is to 
deal with the inorganic oxy- and sulpho-salts and the 
remaining inorganic crystalline compounds, while the 
third and fourth volumes are to treat of the organic 
compounds. The arrangement of the text is that 
each group is described, as regards its general char- 
acteristics, in an introductory statement in large type, 
and this is then followed by the detailed description 
of each member of the group in smaller type. 
An excellent résumé of the crystallography of the 
naturally occurring minerals is given, but it is the 
detailed crystallography of the substances requiring 
to be prepared chemically, and the descriptions of 
which cannot be found elsewhere except by reference 
to the widely scattered original memoirs, that renders 
the book so priceless, for it presents the essential 
results of all chemico-crystallographical investigations 
right up to date. The illustrative figures of crystals 
are neat and clear, and the text easy, the large type 
even luxurious, to read. 
One important feature has been left to the last to 
refer to, namely, that the symmetry of the crystals 
of each substance dealt with is given in accordance 
with the much more scientific method of classification 
recently adopted as the outcome of the completion by 
Schoénflies, Fedorow, and Barlow of the geometrical 
theory of homogeneous structures, which enables the 
particular individual class represented in the substance 
under discussion to be at once identified from among 
the thirty-two possible classes of crystal symmetry. 
In conclusion, with regard to the contents of this 
book, the best of all possible praise can conscientiously 
be bestowed in saying that it is worthy of the master- 
mind that conceived it. 
A. E. H. Turton. 
A NEW WORK ON ORGANIC EVOLUTION. 
The Analysis of Racial Descent in Animals. By 
T. H. Montgomery, jun. Pp. xi+311. (New 
York : Henry Holt and Company; London: George 
Bell and Sons, 1906.) Price tos. 6d. net. 
T would be a most fascinating task to trace the 
evolution of modern methods of dealing with the 
problems of life. Differentiation has taken place so 
extraordinarily quickly. The time is long past when 
one man can attempt to grapple with the whole 
problem. Not only so, but the time seems to be past 
when one man can even be interested in the whole 
problem. Evolutionists may be broadly classified into 
those to whom the problem of evolution is the problem 
of the origin of species and those to whom it is the 
problem of adaptation. The key-note of de Vries’s 
““Mutationstheorie’”’ is the solution of the problem 
of species; we even go so far as to say that this is 
the achievement of de Vries's work. - The logical con- 
lusion, the complete working out of the theory of 
NG@. 1953, VOL. 75] 
natural selection, is reached in Dr. Archdall Reid’s 
‘Principles of Heredity.’’ The interest of the two 
authors is entirely different. De Vries’s interest is 
in the origin of species, Dr. Reid’s in natural selec- 
tion. Darwin’s interest was in both; if we look no 
further than the title of his chief work we can see 
this—* On the Origin of Species by Means of 
Natural Selection.’’ 
The fact that these two interests have segregated, 
and the way in which they have segregated, are both 
very suggestive, and the direction in which they 
point is the same. ‘The fact of segregation suggests 
that the association of the two ideas was unnatural, 
and that they were not capable of union. The way 
in which they have segregated confirms this suspicion. 
For those who devote their attention to the question 
of species reject natural selection, while those who 
elaborate the theory of natural selection find no sup- 
port in the phenomenon of specific difference. All 
possibility of a reconcilement between the divorced 
ideas is put an end to by Meyrick, who probably 
knows more about specific difference than anyone else. 
In his handbook of British Lepidoptera he says 
that, in seeking for the most suitable characters by 
which species may be distinguished, those which can 
in any way be regarded as useful to the species must 
be discarded without more ado. 
It is not surprising that Darwin’s work should have 
borne fruit which segregated in this way. The case 
is thoroughly Mendelian. Darwin’s work was a cross 
between a biological theory of evolution and a social 
and industrial theory of competition. The hybrid, 
more vigorous than either parent, took the world by 
storm. We are now witnessing its posterity separ- 
ating out more or less simply into the two forms 
which were united in the beginning. Just as every 
plant in the F, generation contains yellow and green 
peas, and just as it is not until the next that there 
can be found plants bearing only yellows or only 
greens, so Darwin’s interest was in the ** Origin ot 
Species by Natural Selection,’’? while now we find 
de Vries, who is absorbed entirely with the former, 
and Reid entirely with the latter. 
The immediate result of Darwin's work was the 
flood of energy which spent itself in tracing out the 
genealogical histories of organisms. To such lengths 
did the students of phylogeny go, so remote from 
reality did their speculations become, that the study 
of phylogeny has fallen into discredit in the eyes of 
a great many of those who are looked up to as 
biological thinkers to-day. 
Prof. Montgomery’s interest is centred neither in 
species nor in selection, but in phylogeny. He admits 
that phylogeny has been discredited by the indiscretion 
and shallowness of a number of its exponents, but he 
contends that if we limit ourselves to the strictly 
experimental method we are neglecting an enormous 
range of phenomena. ; 
“For living organisms are in number and variety 
hardly commensurate with the vast assemblage of 
their ancestors. Are we then to leave out of con- 
sideration all this once existing life, simply because 
