November io, 1910] 



NATURE 



39 



diving petrels f)eculiar to the southern seas, and 

 absurdly resembling the little auk of the northern 

 seas both in appearance and habit — diving, fishing, 

 and flying — although widely differing in structure. 

 Darwin wrote of one of them : — 



"No one seeing the bird for the first time, thus 

 diving like a grebe, and flying in a straight line, by 

 the rapid movements of its short wings, like an 

 auk, would believe that it was a member of the 

 family of petrels, the ji^eater number of which are 

 eminently pelagic in their habits, do not dive, and 

 whose flight is usually most graceful and continuous." 



Since the completion of Salvin's catalogue the 

 present monograph has derived much benefit from 

 the considerable additions to the national collection 

 made through the several expeditions sent to the 

 Antarctic regions, among which may be mentioned the 

 vof\-ages of the Discovery, the Southern Cross, the 

 Scotia ; and from the cruises of the Valhalla ; as well 

 as from the expedition sent to the Hawaiian Islands 

 by the Hon. Walter Rothschild ; these together have 

 considerably increased our knowledge of the distribu- 

 tion of the petrels. A full index brings this important 

 volume to a close. 



OUR BOOK SHELF. 



Eugenics, the Science of Human Improvement by 

 Better Breeding. By C. . B. Davenport. Pp. 35. 

 (New York: Holt and Co., 1910.) Price 50 cents 

 net. 



This useful little book consists of two parts. The 

 first is an account of the principles which determine 

 whether a given marriage will produce fit or unfit 

 offspring, the second contains suggestions for future 

 eugenic research. In the somewhat limited class of 

 characters and diseases for which definite Mendelian 

 laws of inheritance have already been made out, it is 

 possible to predict with an approach to certaintv the 

 proportion of the children which will or will not be 

 affected. Thus the malformation of the fingers 

 known as brachydactyly is a Mendelian dominant. 



".\n abnormal person married to a normal will 

 beget 100 per cent., or 50 per cent, abnormal, accord- 

 ing to circumstances, and such a marriage is unfit; 

 but two parents who. though derived from brachv- 

 dactvl strains," are themselves normal, "will have 

 only normal children . . . such a union is entirelv 

 fit." 



Deaf-mutism may be due to any one of a varietv 

 of defects, but in different individuals of the same 

 familv the chance is large that it is due to the same 

 defect. Such defects are often recessives, and jnay 

 appear in the offspring ef normal parents of deaf-mute 

 stocks. Interrnarriage between two such parents, 

 especially of cousins, is 'unfit." .\gain, too, im- 

 becile parents, whether related or not. produce only 

 imbecile offspriner. a fact which should impress those 

 responsible for the long delay in embodving in legis- 

 lation the recommendations of the Roval Commis- 

 sion on the Care and Control of the Feeble-Minded. 



In concluding his suggestions for future inquirv. 

 Mr. Davenport rijihtly points out the contrast be- 

 tween the difficultv of raising funds for such scientific 

 inquiries, and the ease with which monev is obtained 

 for charitable and humanitarian action which often 

 proves to have been ill-judged. 



"One cannot fail to wonder that, where tens of 

 ntillions have been given to bolster up the weak and 

 alleviate the suffering of the sick, no important means 

 NO. 2 141, VOL. 85] 



have been provided to enable us to leai'n how the 

 stream of weak and susceptible protoplasm mav be 

 checked." W, C. D. \V. 



The Book of the Dry Fly. By G. A. B. Dewar. 



New edition. Pp. xxvii + 277. (London: A. and 



C. Black, 1910.) Price 75. 6d. net. 

 The second edition of Mr. Dewar 's " Book of the 

 Dr}- Fly " follows the first after an interval of thirteen 

 years. It is to be regretted that this second edition 

 is, in reality, little more than a reprint of the first ; 

 the art of dry-flv fishing has been developed, and 

 knowledge of the natural history of the trout and of 

 the aquatic creatures upon which it feeds has advanced 

 during these years, and it is a little deceptive to find 

 that references to "last year" in a book with 1910 on 

 the title-page refer to 1896. The deception may even 

 be turned to confusion by the addition of a footnote 

 modifying or contradicting the statements made in 

 the text. 



However much we may regret that the book has 

 not undergone a more complete revision, we may still 

 be glad to find that a second edition has been pub- 

 lished. Mr. Dewar is a student of nature, as well as 

 a fisherman, and he writes with obvious enthusiasm 

 and interest of various chalk and limestone streams 

 and their surroundings. He deals well with the 

 elements of drv-fly fishing, and appears to touch on 

 most points likelv to interest a student of that art. 



There are some matters in which we find Mr. 

 Dewar hard to follow, such as his discussion of the 

 modern higher education of trout, but as a rule his 

 explanations are lucid and his opinions clearly ex- 

 pressed. The grayling is, perhaps, treated with rather 

 scant courtesv in the text, althoug^h the footnotes 

 show signs of a change of view. .•\ singular misuse 

 of the term " dropper " in chapter ii. is obviously the 

 result of an oversight, and this should be corrected in 

 anv future edition. 



.\n attractive feature of the present edition of Mr. 

 Dewar's book is the series of excellent reproductions 

 of water-colour sketches of typical chalk and lime- 

 stone streams ; these should assist the fisherman who 

 does not know the waters of Hampshire or other 

 southern and Midland counties to appreciate the con- 

 ditions which have brought dry-fly fishing into being 

 far more easily than anv mere description in words. 



Last, but not least, there is a good index. 



Die Entu'icklunq des menschlichen Geistes. By Max 

 Verworn. Pp. iv + 52. (Jena: Gustav Fischer. 

 1910.) Price I mark. 

 This is a lecture by the well-known professor of 

 physiology in the University' of Bonn, and is a kind 

 of popular sur\-ey of human development. After 

 dealing with the fact that " the development history 

 of the individual form is a short recapitulation of its 

 race development " (Fritz Miiller) and with the 

 elaboration of this by Haeckel, Dr. \'erworn g^oes on 

 to emphasise the importance of child-study with rela- 

 tion to pedagog:ics. A eulogy of Charles Darwin 

 follows, and a curious and interesting table of sup- 

 posed psychological development from the Eolithic to 

 the present time. 



The British Empire in Pictures. A Geographical Read- 

 ing Book. By H. Clive Barnard. Pp. 64 (London : 

 .\. and C. Black, 1910.) Price is. 6d. 

 The thirty-two excellent illustrations in colour which 

 form the distine;uishing characteristic of this book will 

 ser\-e excellently to predispose young pupils in favour 

 of the study of geography. As a supplement to the 

 more serious work of the class-room, the book should 

 prove useful, and it should not be difficult to get 

 children to read the book as a leisure-hour under- 

 taking. 



