NALORE 
695 

THURSDAY. AUGUST 26, 1915. 
EVOLUTION: OhGANIC AND SOCIAL. 
(1) Evolution and the War. By Dr. P. Chalmers 
Mitchell. Pp. xxv+114. (London: John 
Murray, 1915.) Price 2s. 6d. net. 
(2) Societal Evolution: a Study of the Evolu- 
tionary Basis of the Science of Society. By 
Prof. A. G. Keller. Pp. xi+338. (New York: 
The Macmillan Co.; London: Macmillan and 
Go., Ltd:, 1915.) Price 6s, 6d. net. 
(3) Symbiogenesis: The Universal Law of Pro- 

gressive Evolution. By H. Reinheimer. Pp. 
xxlll+425. (London: Knapp, Drewett and 
Sons, Ltd., 1915.) Price ros. 6d. net. 
vivid 
(1) DS CHALMERS MITCHELL’S 
book begins with an interesting personal 
preface concerning his relations (as student and 
expert and Saturday Reviewer) with Germany. 
The first chapter deals with war and the struggle 
for existence, and contains a destructive criticism 
of von Bernhardi’s “great verity” that “war is a 
fundamental law of evolution.” The second 
chapter refutes some of the widespread miscon- 
ceptions of the struggle for existence, and is a 
timely corrective. Taking the instances of dingo 
replacing thylacine, of the alleged war to the death 
between brown rat and black rat, and of the com- 
petition of cockroaches, the author shows that 
the cases are rarely stated with accuracy, and that 
they do not substantiate the conclusion that an 
incessant internecine warfare obtains throughout 
nature. We think that Dr. Chalmers Mitchell 
draws his bow too tightly when he declares (p. 23) 
that the competition Darwin chiefly thought of is 
internal, amongst the individuals of a species; 
and on the other hand, that he would have 
strengthened his position by extending it, by re- 
cognising that the technical phrase “the struggle 
for existence” includes all the reactions (non- 
competitive as well as competitive) that living 
creatures make to the pressure and stimulus cf 
environing limitations and difficulties. 
The third chapter is devoted to showing that 
even if the struggle for existence were the law of 
organic evolution (an unacceptable way of putting 
it), modern nations are not units of the same 
order as those of the animal and vegetable king- 
dom. A modern nation is not unified by blood- 
relationship; a political community coheres “be- 
cause of bonds that are peculiar to the human 
race.” 
The fourth chapter expresses a wholesome 
scepticism as to the degree in which the stock of 
a nation can be altered by selective or eliminative 
NO. 2391, VOL. 95] 

agencies. Thus the author does not share the 
dread that some biologists have expressed of the 
dysgenic effects of the present war. But we do 
not yet—alas!—know the limit of the sifting. 
The fifth chapter defends the proposition that 
“The most important of the moulding forces 
that produce the differences in nationality are 
epigenetic, that is to say that they are imposed 
on the hereditary material and have to be re- 
imposed in each generation.” ‘The environment 
of the body and the environment of the mind de- 
termine national differences.” 
What is said in regard to the importance of the 
environmental factor carries conviction, but when 
the author expresses his belief that “nurture is 
inconceivably more important than nature,” he 
is opposing complementary, not antithetic, factors, 
and committing the same error as that which he 
condemns in the pronouncements of those who 
have said that in the case of man _ hereditary 
nature has ‘an overwhelmingly greater signifi- 
cance”’ than nurture. 
The book closes, all too soon for our taste, with 
a fine and often eloquent statement of the author’s 
position in regard to the apartness of man from 
other living creatures. Organically we are mam- 
mals and “‘rooted deep in the natal mud ” (an un- 
grateful phrase), but 
“Our possession of consciousness and the sense 
of freedom is a vital and overmastering distinc- 
tion. For man is not subject to the laws of the 
unconscious, and his conduct is to be judged not 
by them, but by its harmony with a real and 
external not-self that man has built up through 
the ages.” 
We think again that the author draws his bow 
too tightly, but it is of great interest to find this 
“hard-shell Darwinian evolutionist, a lover of the 
scalpel and microscope, and of patient empirical 
observation, who dislikes all forms of super- 
naturalism, who does not shrink” (Heaven for- 
fend us from not shrinking from such nonsense) 
“from the implications of the phrase that thought 
is a secretion of the brain as bile is a secretion 
of the liver,” asserting “as a biological fact that 
the moral law is as real and as external to man as 
the starry vault.” 
No one ever quite agrees with his brother’s 
philosophy, but we think that all readers of this 
little book (and may there be many of them !) will 
agree in gratitude to the author. For what he 
has said is marked with sincere and resolute 
thinking, and is especially valuable at the present 
time. 
(2) Prof. Keller is convinced that any fruitful 
study of the science of society must rest on a clear 
understanding of the Darwinian theory, and, 
DD 
