;64 



NATURE 



[January io; 191 8 



people's imag-ination and in reports of successes 

 by the Wrig-ht brothers, and it was scarcely to be 

 wondered at if applications to aerial navigation 

 found no suitable place in a treatise on analytical 

 dynamics. In the twelve years that have elapsed 

 there has been plenty of time for pure and applied 

 mathematicians to provide material that would not 

 occupy merely a single chapter on " The Aero- 

 plane " in a second edition of such a book as this, 

 but might even form a predominating feature 

 of the whole work. Yet on referring to the index 

 we do not even find the word "aeroplane," while 

 the references under " stability " and " resistance 

 of the air " do not lead to any matter suggestive, 

 even vaguely, of the existence of aerial naviga- 

 tion. It may well be a matter of surprise that 

 such an omission should be possible at the present 

 day. 



We cannot lay the blame on Prof. Whittaker, 

 because a book of this kind is necessarily largely 

 an exposition and collation of the work of other 

 writers. But it will be found on closer examina- 

 tion that, outside the problem of small oscillations 

 about a state of steady motion, very little work 

 has been done in advancing what is really out- 

 and-out the most important development of 

 theoretical dynamics, and for the most recent of 

 the developments which have taken place physicists 

 and engineers rather than mathematicians are 

 mainly responsible, much of their work being the 

 property of the Government at present. 



It is, however, rather a pity that Prof. Whit- 

 taker has omitted to introduce the subject under 

 the heading of " stability of steady motion," as this 

 would, at least, afford his readers some stimulus to 

 turn their studies in the right direction. Possibly 

 the author considered it scarcely desirable to make 

 any change until further developments had taken 

 place, and in this second edition he has rather 

 confined his attention to elaborating references to 

 original work on old ground. It is not usual in 

 reviews to repeat what has been said in a previous 

 notice about a first edition. For this reason a 

 detailed account of the actual contents would be 

 scarcely necessary or desirable. The present work 

 will be found of much use by such students of a 

 future generation as are able to find time to extend 

 their study of particle and rigid dynamics outside 

 the requirements of aerial navigation, and it will 

 also afford a valuable source of information for 

 those who are in search of new material of 

 a theoretical character which they can take over 

 and apply to any particular class of investi- 

 gation. 



G. H. B. 



OUR BOOKSHELF. 



Origenes y Tendencias de la Eugenia Moderna. 



By Joaquin Bonilla. Pp. 96. (Liverpool : Daily 



Mail (printers), 1916.) Price 35. 6d. net. 



This introduction to eugenics is intended primarilv 



for Latin America. The author explains the aim's 



NO. 2515, VOL. 100] 



of eugenics, and gives a sketch of the history of the 

 idea of trying to control the agencies which im- 

 prove or impair racial qualities in mankind. Simple 

 expositions are given of Lamarckism, Darwinism, 

 Mendelism, and Weismannism. There is a pleas- 

 ant appreciation of the work of Sir Francis Galton, 

 and the book pays due regard to experimenters 

 and biometricians alike. The endeavours of the 

 Eugenics Education Society are recognised, as well 

 as the work of Prof. Karl Pearson's Eugenics 

 Laboratory. So up-to-date is the book that men- 

 tion is made of England's " Baby Week " and of 

 the withdrawal of the veto on the representation 

 of certain plays by Ibsen and Brieux. A chapter 

 is devoted to eugenic activities in the United 

 States. 



The author has the wise and kindly intention 

 of familiarising Spanish-speaking young people 

 with the aims and methods of eugenics, and he 

 seems to us to have written a clear and terse intro- 

 duction to the subject. We should like to have 

 seen some recognition of what is practicable in the 

 way of ameliorating environment and function,, 

 and improving nurture generally. For the eu- 

 genic ideal does not, and cannot, stand alone. In 

 a short book like this it should have been readily 

 possible to avoid disfiguring verbal errors, such as 

 Seleeby, Burcke, Havelock Elliott, and Weisner; 

 but these are very small flies indeed in the care- 

 fully prepared ointment. We wish the book suc- 

 cess. 



The Human Body: An Account of its Structure 

 and Activities and the Conditions of its Healthy 

 Working. By Prof. H. Newell Martin. Tenth 

 edition, thoroughly revised by Prof. E. G. 

 Martin. Pp. xviii + 649. (New York : H. Holt 

 and Co., 1917.) 



A BOOK which has reached a tenth edition 

 needs but little recommendation. The late 

 Prof. Newell Martin's work, like all that he did, 

 is excellent. It is rather more bulky than 

 the majority of books of an elementary nature ; 

 but, like these, it is a compendium of anatomy and 

 physiology designed, not for the student of medi- 

 cine, but for the general reader who desires to 

 become acquainted with the mechanism of his own 

 body and the reasons for the laws of health. It 

 is naturally the physiological side which is mainly 

 dwelt upon, only so much of structure being 

 described as is necessary for the understanding 

 of function. The present edition has been brought 

 well up to date, and, like the only other book 

 with which we may compare it, Huxley's 

 "Elementary Physiology," has doubtless still 

 before it a long and useful life. 



A welcome feature of the book is the appendix, 

 in which instructions for practical work are given 

 in detail. Much of this will need a laboratory, 

 but it is astonishing how much useful practical 

 work can be performed without elaborate appara- 

 tus, and with the resources which are available 

 to nearly every teacher. 



