February 13, 1908J 



NATURE 



339 



Although the author accounts for many of the other 

 surface features and changes as recorded on the 

 Martian disc, he is unable to suggest any satisfactory 

 explanation of the doubling of the canals. 



Enough, perhap-i, has been said to indicate that 

 in these pages we have some very original ideas on 

 a subject of all-absorbing interest. It must neverthe- 

 less be left to the reader to form his own judgment 

 as to the probability of the views put forward when he 

 has carefully read the book. 



We can unhesitatingly recommend this book to a 

 verv large circle of our readers, and more especially 

 to those who have followed the previous publications 

 relating to this subject. The last word on this difR- 

 cult question has not been said yet, and the present 

 issue will very likely re-kindle the flame. 



\\'lLLIAM J. S. LOCKVER. 



AGKICLLTL'KE IN FRANCE. 

 (i) Races bovina. Fra]ice — Etranger. Pp. 426. 

 Price 5 francs. (2) Races chevalincs. Pp. viii + 

 4(17. Price 5 francs. By Prof. Paul Diftloth. En- 

 cyclopedic agricole. Zootechnie. (Paris : J. B. 

 Bailliere et Fils, 1908.) 

 T .\ the first of these volumes of the Encyclopedia Prof. 

 Diffloth claims that special attention has been paid 

 to varieties, to methods of selection and to breeding, 

 and the author is to be congratulated on the success 

 of his efforts. The book is a very valuable contribu- 

 tion to our knowledge of domesticated cattle; it treats, 

 with commendable breadth and sufficient detail, not 

 only of the characteristics of a great number of breeds 

 and varieties of those breeds, but of certain of the 

 phvsical conditions under which they thrive and of 

 their geographical distribution. 



Part i., which occupies thirty-four pages, begins 

 with a short description of external features, head, 

 bodv, limbs, teeth, horns, coat and colour, followed 

 bv brief notes on some of the anatomical variations 

 which are specially marked in different races. 



Part ii. fills the remainder of the book. The classi- 

 fication adopted by the author is based partly on San- 

 ^on's scheme of skull measurement, by which all 

 s.pecies are divided into two main groups in accord- 

 ance with the angle formed by a line drawn across 

 the forehead at the base of the horns and a line from 

 the base of one horn to the outer edge of the eye of 

 the same side. When the angle so formed is a right 

 angle, the type is recognised as brachycephalic, when 

 it is obtuse as dolicocephalic. It is pointed out, how- 

 ever, that such classification is by no means a suffi- 

 cient guide, and that various other external features, 

 such as the form of the crest between the horns, the 

 curve of the horns themselves, &c., must also be 

 taken into account for practical purposes. 



Twelve main races are recognised, and these are 

 again subdivided into eighty-five varieties, as fol- 

 lows : — 



(i) Low countries, with fifteen varieties; (2) Ger- 

 man, three varieties; (3) Irish, five varieties; (4) 

 Alpine, eight varieties ; (5) .\quitaine, eight varieties; 

 NO. T998, VOL. '/■/I 



(6) Scythian, eight varieties; (7) Vendeenne, seven 

 varieties; (8) .'\uvergnate, three varieties; (9) Jurassic, 

 fourteen varieties; (10) Iberique, six varieties; (11) 

 Asiatic, seven varieties; (12) Scotch, represented only 

 by the breed of that country. 



Each variet)' is described; its origin, relation to 

 other breeds, and the effects of crossing are discussed; 

 its special capabilities are examined; the physical con- 

 ditions of the geographical area it inhabits are 

 generallv noted, and their possible effect upon the 

 breed is referred to. 



A series of seven maps is of special interest. They 

 are designed to show the areas over which certain 

 races and varieties range, and in some cases their 

 special breeding area is further distinguished. With 

 two exceptions these maps refer to French breeds, 

 the Dutch and .\ustro-Hungarian races being the only 

 others so treated. This scheme is a most suggestive 

 one, and if consistently carried out would be a very 

 valuable aid both to the student and the practical 

 breeder. 



The text is full of valuable information concisely 

 and clearly presented, especially valuable to English 

 readers where it treats of French breeds. Besides 

 figures in the text, many of which leave very much 

 to be desired, there are forty plates, photogravures of 

 selected animals. 



The space at our disposal allows of only a very brief 

 notice of the second volume. This book is equally 

 carefully compiled, and is a valuable aid to the student, 

 especiallv in relation to the natural conditions under 

 which the various races and varieties of the horse 

 thrive. 



The author's classification scheme will not, perhaps, 

 satisfv many authorities, but his descriptions of the 

 characteristics of the very numerous varieties he re- 

 cognises are clear and unbiased, and the figures and 

 plates are good. 



His statistics regarding the horse population of the 

 world are no doubt open to criticism, but they cannot 

 be questioned in relation to the conclusion he draws 

 that the advent of the motor-car and agricultural 

 machinerv has been followed by an increase both in 

 the numlDers and value of horses. The view that 

 Government aid is necessary for the breeding of cer- 

 tain classes of horses in this country receives substan- 

 tial support from the author's description of the 

 results gained by the care given and the large sums 

 expended by his own Government for this purpose. 

 Short chapters on the ass and the mules conclude the 

 volume. 



CHEMISTRY IX THE SEVENTEENTH 

 CENTURY. 

 Medico-Physical Works of John Mayoiv (1674). Pp. 

 xxiii4-3,3i; with 6 plates. (Edinburgh: The 

 .Uembic Club, 1907.) 



ALTHOUGH the name uf John Mayow is well 

 known to chemists, there are few who are 

 acquainted with his works. Even the majority of the 

 historians of chemistry have been content to acquire 



