December 8, 1923] 



NA TURE 



82 



eugenics and a conviction that statesmen and law- 

 makers alike have failed to realise how fully any in- 

 telligent attempt to improve the conditions and 

 qualities of the human race must be founded on a 

 knowledge of the manner in which qualities arise, are 

 inherited, maintained or lost, have driven the author 

 to glean from many sources. Thus he has been able 

 to assemble in the present volume a crowded record 

 of observations on the physical and mental characters 

 of man, the results of the blending of races, the 

 problems of population, and other aspects of eugenics, 

 the main practice of which appears to be the production 

 in the human frame of ready remedies for the evils of 

 our social systems. 



A general list of works bearing more or less directly 

 on the infant subject of eugenics, and a bibliography 

 of papers which have largely contributed to the matter 

 of the text, complete the volume, and provide both 

 ample reference for the general reader who would probe 

 more deeply into recorded facts and opinions, and proof 

 of the lively interest which has grown within the last 

 two decades in Nature's laws which make or mar man's 

 prospects from birth. 



To maintain a well-bom race is a natural aspiration 

 involving no necessarily clear conception of the acme 

 of human development of qualities either physical or 

 mental ; for although we cling to a vague ideal of a 

 healthy mind in a healthy body and define more or less 

 clearly the standards whereby we judge our fellow- 

 creatures, there is no guarantee from the long pages of 

 descent that the standards of human well-being for 

 which we strive have kept in motion and in strength 

 the main stream of human life. 



It is well to realise how temporary are our aims, and 



that, in the practice of eugenics, our purposes are 



moulded more by our social systems than by a wide 



knowledge of whence man came and how, and of 



whither he is going and why, in the inexorable drifts 



of countless generations. To render better the span 



o f life for our descendants is indeed a noble aim, the 



^Bblisation of which must be based on a study of great 



^^■bal trends rather than on the application by one 



|^m:ial cast to another of a knowledge of chromosomes, 



\-linked inheritance, or the incidence of feeble- 



iiindedness and colour-blindness. For man has come 



down the ages for good or ill by paths which neither 



knowledge of inheritance nor a man-formed scheme 



1 eugenics could have controlled effectively, and so he 



will go, despite our best endeavours, by the ceaseless 



drive of world-forces which eugenic practice can never 



mould to our will. 



Much space is devoted in the text of the present 

 \olume to such topics as stature, eye-colour, hair- 

 distribution, brachydactyly, and cataract, and to the 

 NO. 2823, VOL. 112] 



occurrence of feeble-mindedness among the destitute, 

 musical aptitude, and the limits within which characters 

 of a parent persist in the offspring. But on the vital 

 questions which are ever before us of the origin and 

 meaning of any single character which declares itself 

 in a life-span with a fate to be sealed in descent, there 

 is silence. It is well that this should be fully realised, 

 for it marks much of the current literature on eugenics, 

 and stamps it as a speculation in futures of which we 

 know nothing for lack of knowledge of the past. For 

 Mendelian inheritance, on which eugenic practice so 

 fully rests in its quest for the betterment of the human 

 race, is little more than an elaborate distributing agency 

 which deals in complex characters of unknown origin 

 for which the future is obscure. 



The book is well written and adequately illustrated : 

 it will serve admirably as a guide to those who seek 

 an honest statement of the present position of the 

 principles on which the practice of eugenics is being 

 built to-day. J. McL. T. 



Our Bookshelf. 



Ultraviolet Radiation: its Properties, Production, 

 Measurement, and Applications. By M. Luckiesh. 

 Pp. xi + 258 + 12 plates. (London: Crosby Lock- 

 wood and Son, 1923.) 215. net. 



When Scheele in 1777 projected the visible spectrum 

 upon silver chloride, he was on the verge of discover- 

 ing ultraviolet radiation, but it escaped his attention. 

 Ritter in 1801 noted the effect on silver chloride of 

 what proved to be this new type of radiation. This 

 was the starting-point of a series of discoveries of photo- 

 chemical effects made in the early part of the nine- 

 teenth century. The limit of transparency of ordinary 

 glass is in general at about 340 millimicrons. Quartz 

 crystals were found to be transparent as far as 185 

 millimicrons. Instruments employing quartz made it 

 possible to extend the ultraviolet spectrum greatly, and 

 by using fluorite Sclumiann extended the explored 

 region from 200 to 120 millimicrons. Lyman placed the 

 light source in an exhausted spectrograph chamber, and 

 by employing a reflection grating was able to extend the 

 known spectrum to about 50 millimicrons. Recently, 

 Millikan has spanned the gap between these short 

 ultraviolet rays and X-rays. 



A detailed account of the experimental work that 

 has been done on the subject of ultraviolet radiation is 

 provided in a recent work by Mr. M. Luckiesh of the 

 Nela research laboratories. The author states that his 

 aim is to present authentic data of such scope as to be 

 useful to those who are interested in the subject. 

 Theory has purposely been subordinated to experi- 

 mental facts because the latter are not affected by tlie 

 inevitable changes in theory. The result of his labours 

 is to furnish a storehouse of information which will be 

 of service to the chemist, the physicist, the engineer, the 

 biologist, the ophthalmologist, and the physician, for to 

 each this form of energy is of practical value. 



After a short introduction and an account of the 



