APRIL 19, 1901.] 
ters; a character which is constant and there- 
fore reliable for purposes of differentiation and 
classification in one suborder or family, in an- 
other may be highly variable. This fact must 
be recognized in framing classifications. 
The author retains with a few minor changes 
the classification proposed in the catalogue of 
the Jurassic bryozoa. In the present state of 
knowledge some scheme of classification is a 
necessity and yet but a temporary expedient. 
Our knowledge of the derivation, purpose, func- 
tion and relative importance of the various 
structures found in fossil bryozoais still too im- 
perfect to enable an abiding classification to be 
framed. After all, the main purpose of a classi- 
fication is to provide a scheme for maintaining 
an easy grasp upon relationships. : 
At the present time the best work that can be 
done is just the kind which our author does in 
this work, the giving of careful, close, accurate 
description with some account of the variations 
exhibited by a ‘species,’ with figures from which 
the form can be certainly recognized, and the 
careful, accurate, critical examination of the 
literature to weed out the synonyms. The au- 
thor describes a considerable number of new 
species, showing that even in this direction there 
remains agreat deal to be done. To the stu- 
dent of the bryozoa in general and the Cre- 
taceous bryozoa in particular, the present vol- 
ume must prove an indispensable working 
requisite. 
J. M.N. 
The Human Nature Club; An Introduction to the 
Study of Mental Life. By EDWARD THORN- 
DIKE, Ph.D. Longmans, Green & Co. 1901. 
8vo. Pp. 235. 
This is an attempt to present the main facts 
of psychology in the form of a story, or at least 
of dialogue. Of this aspect of the essay the 
author says: ‘ Dramatically it is an atrocity.’ 
Such frank disclaimer makes any further com- 
ment ungracious. And yet it would certainly 
have added much to the success of the under- 
taking not to have so entirely ignored the 
artistic factor in the presentation. It must, 
however, be viewed merely as a pedagogic aid 
to the popularization of the study of psychology, 
and particularly as a means of arousing interest 
SCIENCE. 
621 
in the significance of the every-day mental life 
among every day people. As such it is an 
eminently sound and helpful presentation. It 
is also more than this, as it presents a per- 
spective of the importance of some of the 
factors of mental assimilation, which bear the 
mark of close and original thinking. This is 
particularly true of the discussion of the for- 
mation of habits, with reference to the effect of 
special upon general training. In the main it 
is an appropriately eclectic treatment of the 
primary elements of our mental nature. The 
Human Nature Club is a very artificial assem- 
blage of persons, who discuss, with rare single- 
ness of purpose, ‘ what the brain does,’ and the 
‘things we do without learning’ and ‘the dif- 
ferent ways of learning’; consider the senses 
and memory and attention and trains of 
thought and mental imagery and suggestion 
and imitation and our emotions and our actions 
and character, and some other yet more com- 
plex and deeper questions. Socrates would 
certainly be shocked at the modern speed with 
which conclusions are drawn from a few 
sporadic, and yet significant, illustrations, 
with but little allowance for analysis or dia- 
lectic. But this is inevitable, if the book is to 
cover its ground ; and after all, the characters 
of the dialogue do not really draw these con- 
clusions, but only restate them from such 
worthy authorities as James and others. The 
psychological matter is well grounded, sug- 
‘gestive, discriminatingly used and clearly set 
forth. The query will arise with reference to 
the proof of the pudding, which according to 
modern notions is not in the eating, but in the 
digestion thereof. That the book may prove 
palatable to certain palates, it is easy to be- 
lieve ; but whether persons with sufficient ma- 
turity of miod to consider psychological ques- 
tions at all should not be at once placed on 
more strenuous diet, is a question upon which 
teachers of psychology are likely to hold 
diverse opinions. Yet with whatever training 
they may desire their pupils to approach the 
study of mental phenomena, it would be mere 
perversity to fail to recognize that there is in 
this country a large class of persons who do 
‘study ’ psychology, are genuinely interested, 
and are likely to be approachable only by ap- 
