504 



NATURE 



[February i6, 191 i 



authors have given us an admirable collection of exer- 

 cises, and if students will take the trouble to work 

 through these 427 questions conscientiously they 

 will find it excellent training for the solution of 

 practical problems. Gisbert Kapp. 



ASPECTS OF DARWINISM. 



(1) Darwinism and Human Life. The South African 

 Lectures for 1909. By Prof. J. Arthur Thomson. 

 Pp. xii + 245. (London: Andrew Melrose, 1909.) 

 Price 55. net. 



(2) Darwinism and the Humanities. By Prof. James 

 Mark Baldwin. Pp. xi+i2S. Second edition. 

 (London ; Swan Sonnenschein and Co., 1910.) 

 Price 3s. 



(i) pROF. J. ARTHUR THOMSON is well known 

 ■^ as one of the ablest and most jjudicious of recent 

 critics of the Darwinian position. Fully appreciative 

 of the extraordinary value of Darwin's contribution to 

 evolutionary theory, he is yet ready to give an im- 

 partial hearing to all genuine investigators in the field 

 of bionomics, whether their results appear to be 

 favourable or adverse to the views advanced by Dar- 

 win. Like some other writers who strive to maintain 

 a candid and unbiassed attitude in the face of con- 

 flicting opinions, he is liable to the usual penalty of 

 open-mindedness ; the imputation, that is to say, of 

 indecision — in homely phrase of " running with the 

 hare and hunting with the hounds." Such an impu- 

 tation, if meant as a reproach, would be in Prof. 

 Thomson's case undeserved; if intended as a tribute 

 to his faculty for seeing both sides of a question, it 

 would be justified. 



The present volume, which is a reproduction in 

 permanent form of a series of lectures delivered 

 under the auspices of the South African Associa- 

 tion for the Advancement of Science, is a good 

 example of the author's skill in popular exposition. 

 He does not shirk difficulties, but deals with them in 

 a lucid and popular manner. In most respects he 

 may be trusted as a faithful interpreter of the views 

 botn of Darwin and of his successors ; here and 

 there, however, in our opinion, he goes somewhat 

 astray. A notable instance of this is his treatment 

 of Darwin's term, the "Struggle for Life." There 

 can be no reasonable doubt that the leading idea in 

 the mind of the originator of the phrase was com- 

 petition — mainly between organisms of the same kind. 

 Nothing is gained, and some confusion is introduced, 

 by enlarging the conception so as to include resist- 

 ance to adverse external conditions, or the strife 

 between carnivorous animals and their pre}'. The 

 evolutionary significance of these latter phases of 

 organic existence lies in the fact that they necessitate 

 competition, whether active or passive, and conse- 

 quent selection, between generally similar individuals 

 exposed to their influence. Here, in our opinion, 

 Weismann, Haeckel, and Ray Lankester are right, 

 and the author of " Darwinism and Human Life " is 

 wrong. 



On the question of the transmissibility of acquired 

 characters or "somatic modifications," Prof. Thom- 

 son takes- the line (and indeed he could scarcely do 

 NO. 2155, VOL. 85] 



otherwise) that " we do not know of any clear 

 case which would at present warrant the assertion 

 that a somatic modification is ever transmitted from 

 parent tc offspring." At the same time he fully recog- 

 nises that these somatic modifications are very common, 

 that they are of much individual importance, that they 

 may have an indirect influence through the body on 

 the offspring, and, in short, may exercise an indirect 

 control over evolution in several ways. But he rightly 

 denies that evidence exists of their influencing the 

 germ-plasm in a Specific or representative manner. 

 That the germ-plasm can in certain cases be per- 

 manently altered by external conditions artificially 

 induced was surmised many years ago by Weismann 

 (for Chrysophanus phlaeas), and shown by Fischer (in 

 Chelonia caja). The same fact has now been demon- 

 strated on an elaborate scale by the careful experi- 

 ments of Tower on Leptinotarsa. But it is hardly 

 necessary to point out that these results go no way 

 towards proving the " Lamarckian " contention. 



Not the least interesting passages of Prof. Thom- 

 son's book are those in which he deals with the 

 relation of Darwinism to social and political ques- 

 tions. But the bearing of the doctrine of natural 

 selection on human affairs in the widest sense re- 

 ceives a still more thorough and extended treatment 

 in Prof. Mark Baldwin's volume, entitled "Darwin 

 and the Humanities," of which a second edition 

 has lately been published (2). The special value 

 of Prof. Baldwin's contribution to Darwinian 

 literature lies in the fact that he is not 

 primarily a biologist with an interest in philosophy, 

 but a philosopher who seeks in biological data the 

 suggestion and justification of his philosophical 

 method. Hence the importance of his conviction, 

 reiterated in the course of the present and other 

 treatises, that "natural selection is in principle the 

 universal law of genetic organisation and progress in 

 nature — human nature no less than physical nature." 

 This, he affirms, 



"Is the conclusion to which the lines of evidence we 

 now have distinctly point ; and while this has some- 

 what the appearance of a forecast, it is one of those 

 reasonable forecasts which give life and interest to the 

 progress of science and philosophy alike." 



The application of this view to the problems of 

 psychology, the social sciences, ethics, logic, episte- 

 mology, philosophy, and religion, is the object of the 

 present work, which, though it is in the author's 

 words "no more than an outline or sketch," yet 

 succeeds in conveying in a comprehensive and effective 

 manner the suggestion of a philosophic method in 

 reasonable harmony with scientific fact^ and values. 



A characteristic and consistent feature of Prof. 

 Baldwin's conception of Darwinian theory is the 

 emphasis that he lays on the psycho-physical char- 

 acter of the material presented to the operation of 

 natural selection. Bound up with this is the recog- 

 nition of mental plasticity, or, to use Sir E. Ray 

 Lankester's term, " educability," as an all-important 

 factor in progressive development. One outcome of 

 the view here spoken of is the rather unfortunately 

 named principle of "organic selection" — a principle 

 incidentally recognised, as the author shows, by 



