December 4, 1919] 



NATURE 



*35i 



principles of synthetic composition were borrowed 

 from the Old World." 



The lecture notes are unfortunately somewhat 

 scrappy, and Prof. Elliot Smith apologises for the 

 cjrcumstances which led both to this defect and to 

 the not infrequent repetitions. The book also 

 lacks an index, which would add much to its use- 

 fulness. It is, however, a veritable mine of in- 

 formation on the subjects with which it deals, 

 with numerous references to literature,, and science 

 is indebted to the John Rylands Library for under- 

 taking- the publication. 



EUGENICS. 

 (i) Lectures on Sex and Heredity delivered in 

 Glasgow, 1917-18. By F. O. Bov;er, J. Graham 

 Kerr, and W. E. Agar. Pp. vi+119. (Lon- 

 don: Macmillan and Co., Ltd., 1919.) Price 

 55. net. 



(2) Eugenics and Environment. By Prof. C. Lloyd 

 Morgan. Pp. 82. (London : John Bale, Sons, 

 and Danielsson, Ltd., 1919.) Price 2S. net. 



(3) La Selection Humaine. By Prof. Charles 

 Richet. (Bibliotheque Scientifique Inter- 

 nationale.) Pp. iii-i-262. (Paris: Librairie 

 Felix Alcan, 1919.) Price 6.60 francs. 



nPHESE three books illustrate three somewhat 

 -^ different methods of setting the problem of 

 eugenics before the general reader. The aim of 

 the excellent little book by Prof. Bower, Prof. 

 Graham Kerr, and Dr. Agar is to set forth the 

 indispensable facts and principles, and leave the 

 reader to draw the moral. It is not perhaps in- 

 tended to deal with eugenics at all, but it is one 

 which enthusiasts for eugenic propaganda will 

 find very valuable. It consists of six lectures on 

 the more elementary facts of sex, reproduction, 

 and heredity in plants and animals. The first four 

 lectures, two on plants and two on animals, deal 

 with the subject in the two kingdoms in similar 

 fashion, beginning with examples of reproduction 

 and conjugation (syngamy) in the Protista, and 

 passing through the simpler Metaphyta and 

 Metazoa to the more complex phenomena of the 

 highest plants and animals. No one who has a 

 natural interest in living things, but has had 

 no systematic training in biology, can fail to find 

 these lectures interesting ; those on plants are 

 perhaps unnecessarily technical here and there, 

 but with the assistance of the excellent illustra- 

 tions any reasonably educated person should find 

 them easy and interesting to read. 



In the last two lectures Dr. Agar takes up the 

 subject of heredity, begins with the phenomena 

 of fertilisation, cleavage, and the early segregation 

 of the germ-cells in Cyclops as an introduction to 

 the conceptions of soma and germ-plasm and the 

 material basis of inheritance, and then proceeds 

 to give a short but lucid account of Mendel's law. 

 In the last lecture he takes up heredity in Man. 

 He points out that, since the characters in Man 

 which are known to follow Mendel's law are com- 

 paratively few, and in general of small practical 

 importance, human heredity must be studied in 

 NO. 2614, VOL. 104] 



practice chiefly by the statistical methods of the 

 biometric school. Of these he gives a lucid 

 elementary description, illustrated by actual 

 examples taken from the papers of Pearson, 

 Heron, Schuster, and others, and shortly points 

 out the bearing of the facts on eugenic proposals. 



(2) Prof. Lloyd Morgan's little book is frankly 

 an elementary text-book of eugenics. It deals with 

 variation in human characters as illustrated by 

 the normal curve of error, the principles of cor- 

 relation, and the method of finding the correla- 

 tion coefficient, very shortly with Mendelian 

 heredity, and finally with acquired characters, 

 selection, and the relation of biological characters 

 to social tradition and civilisation. It is written in 

 a pleasant and almost colloquial style, but suffers 

 not infrequently from a certain obscurity of dic- 

 tion — e.g. in describing a correlation table (p. 33) : 

 "Along the left-hand vertical side the stature of 

 the sons is given in ascending order read down- 

 wards " (our italics). Again, on p. 32 a mislead- 

 ing definition of perfect correlation is given, 

 which is corrected at the bottom of the same page, 

 a treatment which does not conduce to clearness. 

 On p. 47 there is, doubtless by a slip, the mislead- 

 ing statement : " If blue eyes mate with brown 

 eyes, one child in four may be blue-eyed." We 

 feel also that the booklet suffers from being illus- 

 trated by purely imaginary examples the simplicity 

 of which may give a false impression. Dr. Agar's 

 account of biometric methods compares favour- 

 ably with it in this respect. Nevertheless, it is 

 in most respects an admirable elementary intro- 

 duction to the subject, such as might well be used 

 by those who wish to follow it up more fully by 

 further reading. 



(3) Prof. Richet's book has more of the char- 

 acter of an essay. It does not profess to set 

 forth specific facts, but takes the facts for granted, 

 and discusses the conclusions to be drawn from 

 them. The main thesis of the author is that if 

 selection can do such great things with domestic 

 animals and plants, it could, if applied, do equally 

 great things with man, and that the only hope for 

 mankind in the future is in its application. The 

 aim of life is happiness ; progress is the increase 

 of. total happiness; this can be gained through 

 science alone; it is limited only by the limits 

 of the human mind, and these limits might be 

 almost indefinitely extended by suitable selection. 

 Selection must be of several kinds. In the first 

 place, the white race is indisputably superior, 

 and crossing with black or yellow gives bad 

 results. All race-crosses must therefore be pro- 

 hibited. Within the white race all defectives must 

 be prevented from reproducing ; seriously defective 

 infants must not be allowed to live, and those 

 found defective in later life must be segregated. 

 Finally, positive encouragement must be given to 

 marriage of the superior, especially between those 

 superior in the same . respect. The author's 

 enthusiasm leads him at times to rather wild state- 

 ments. He calls deaf-mutes (sourds-muets) "ces 

 dbauches d 'humanity, ces produits disgraci^s . . . 

 ces pauvres avortons," words which can only dis- 



