January 15, 1920] 



NATURE 



499 



little technical as possible. The biology and some 

 elementary points of structure of each group are 

 briefly considered, and useful keys are provided 

 to aid the reader in finding at least the generic 

 name of the more common organisms which the 

 author has collected from a single pond in New 

 Jersey. Special attention has been devoted to 

 certain groups — e.g. Gastrotricha, Rotifera, 

 Polyzoa. Here and there the desire to be non- 

 technical in terminology has been carried a little 

 too far — e.g. the egg-masses of Cyclops should 

 not be called "external ovaries," and the term 

 " contractile vesicle " is not a good substitute for 

 " contractile vacuole " — the latter term could have 

 been quite easily defined. Helpful illustrations 

 (ig8) as aids in diagnosis of the genera are given, 

 but we would suggest that when the book reaches 

 a fifth edition figures should be added of some 

 of the commoner transparent animals, e.g. a 

 rotifer, a polyzoon, Daphnia, in which the 

 chief internal organs are clearly shown and 

 labelled. 



OUR BOOKSHELF. 



The Elements of Astronomy for Surveyors. By 

 Prof. R. W. Chapman. Pp. x + 248. (London : 

 C. Griffin and Co., Ltd., 1919.) Price 55. net. 

 Sir John Herschel's dictum in his well-known 

 panegyric on star-catalogues, that "every well- 

 determined star from the moment its place is 

 registered is as effective for mapping down the 

 intricacies of a petty barony as for adjusting the 

 boundaries of transatlantic empires," may be taken 

 as the raison d'etre of this book. The author is 

 professor of mathematics and mechanics in the 

 University of Adelaide, and doubtless the southern 

 continent gives scope for surveying on a large 

 scale in which astronomical observation is a neces- 

 sity. 



The book is on conventional lines, the first six 

 chapters dealing with the elements of geometrical 

 astronomy, including one which explains at some 

 length with examples the conversion of sidereal 

 into mean time and similar arithmetical processes. 

 The latter half of the book consists of chapters 

 on the determination of true meridian, on azimuth 

 of a mark, of latitude, time, and longitude. Most 

 of the recognised methods are concisely explained, 

 and illustrated in some cases by examples taken 

 from actual experience. Use is made of the 

 observation of circumpolar stars at elongation for 

 determination of azimuth, and for time the ob- 

 servation of altitude of the sun or a star near 

 the prime vertical is recommended and discussed 

 in full detail. The inclusion of a few pages on 

 the almucantar is a useful addition to the book, 

 which will fulfil its intended purpose of providing 

 an elementary exposition of the principles of the 

 formulae used by the surveyor. 



NO. 2620, VOL. 104] 



i Organic Chemistry for Students of Medicine. By 

 j Prof. James Walker. Second edition. Pp. xi-t- 

 I 332. (London: Gurney and Jackson; Edin- 

 I burgh : Oliver and Boyd, 1919.) Price lox. 6d. 

 i net. 



j This second edition of Prof. Walker's book for 

 medical students does not differ substantially from 

 1 the first edition as issued in 191 3. It may, how- 

 I ever, be useful to direct the attention of medical 

 students and their teachers to a volume which 

 ; has been written specially to suit their require- 

 ments, and the value of which is shown by the 

 publication of a further issue. 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for 

 opinions expressed by his correspondents. Neither 

 can he undertake to return, or to correspond with 

 the writers of, rejected manuscripts intended for 

 this or any other part of Nature. No notice is 

 taken of anonymous communications.] 



Promotion of a Plumage Bill. 



All lovers of animals must sympathise with any 

 efforts to prevent the ruthless destruction of bird-life 

 for trade purposes, referred to by Mr. H. J. Massing- 

 ham in his letter in Nature of December 25. It 

 is open to grave doubt, however, whether the measures 

 announced are the best that can be devised or will 

 meet with a sympathetic following. They are the 

 formation of a "Plumage Bill group," designed to 

 fight the plumage trade and to bring pressure upon 

 the Government to introduce a Bill forbidding the 

 importation of all birds' skins for millinery purposes, 

 with a few exceptions. 



From time immemorial plumage has been employed 

 to satisfy the decorative and aesthetic instincts of 

 mankind, though to-day public opinion is rightly 

 determined that it must be procured under conditions 

 conforming with our humane sentiments. We may 

 well inquire, therefore, whether the aesthetic demands 

 for plumage can be met without outraging these. 

 The ostrich in South Africa supplies a forcible case 

 in point. In times past the wild bird was hunted for 

 its precious plumes, and would have become almost 

 extinct ere this had not its domestication been under- 

 taken. As it is, the wild bird is now preserved and 

 is increasing in numbers, and hundreds of thousands 

 of domesticated birds lead a pampered existence on 

 the ostrich farms. A big industry has arisen of the 

 highest importance to agricultural South Africa, repre- 

 senting in pre-war days an annual export value of 

 about 3,ooo,oooZ. 



It is submitted that what has been accomplished 

 with the ostrich may be possible with other birds 

 supplying ornamental plumage ; that, like it, others 

 may give rise to industries and yield their plumage 

 in conformity with the highest humane demands. 

 One ventures to suggest that, instead of pursuing a 

 repressive policy, the efforts of Mr. Massingham and 

 his associates would be better directed in instituting 

 studies and investigations as to conditions under 

 , which plumage-birds could be reared on an industrial 

 ; basis. 



i Mr. Massingham appears to have an unworthv 

 j view of the issues involved in his announcement, for 

 j in the plumage trade he sees " no other purpose than 

 j to feed the profits of a small band of East End traders 

 ] and to satisfy the frivolity of some women." Though 

 ostrich plumes are exempted from the operations of the 

 proposed Bill, yet so sensitive is the inter-relationship 



