4 o 



NATURE 



[July 13, 191 1 



extensive and intensive that he made no pretence of 

 keeping pace with it. 



(2) Prof. Leche's book made its first appearance 

 in Swedish at the time of the Darwin celebrations in 

 1909, and when the time came for the preparation of a 

 second edition he made his interesting work available 

 to a wider circle of readers bv issuing this German 

 edition. 



The book is a simple and lucid description of the 

 growth of evolutionary ideas, with an account of the 

 men to whom we are indebted for this new learning. 



Unlike Haeckel's treatise, which takes the form of 

 lectures addressed to students of biology, but in virtue 

 of its lucidity has become, nevertheless, a popular 

 treatise, Leche's book is obviously written for the 

 educated public in general, and therefore omits certain 

 topics discussed bv Haeckel, which are properlv in- 

 cluded in a treatise on biology, but not in works for 

 wider circulation. 



It is somewhat disappointing to the biologist familiar 

 with the author's important contributions to compara- 

 tive anatomv that Prof. Leche should have chosen to 

 cast his book in so popular a mould. It would have 

 been instructive to have had more information con- 

 cerning the higher primates from one who is so greal 

 an authority on the other end of the mammalian 

 phylum. But Prof. Leche has chosen the rdle of 

 expositor, mainly of other people's work, and we are 

 duly grateful for his clear statement of generally 

 accepted views regarding man's origin and develop- 

 mental history. 



The book opens with an exposition of the growth 

 of the theory of evolution, with an account of the 

 work of Charles Darwin, his predecessors, co-workers, 

 and followers, and it discusses the modern conflict 

 between the teaching of Weismann and " Neo- 

 Lamarkismus," expressing the opinion, for which he 

 claims the support of Darwin himself, that the origin 

 of species can be explained only by admitting the 

 potency of the essential factors emphasised by both 

 schools. 



The second chapter is a simple exposition of man's 

 place in the vertebrate series, explained by reference 

 to the facts of comparative anatomy and embryology. 

 Chapter iii. gives an account of the nature of the 

 palaeontological record, and deals at some length with 

 the histories of the various vertebrate groups that 

 have been recovered bv this means, most of the space 

 devoted to mammals being filled by the familiar story 

 of the horse. The next three chapters deal respectively 

 with man's structure as illuminated bv comparison 

 with that of other vertebrates ; the light thrown on 

 man's development by comparative embryology ; and 

 the nature and significance of rudimentary organs in 

 the human body, the pineal body, the third eyelid, the 

 palatal ridges, the coccyx, superfluous hair and teeth, 

 and the vermiform appendix being the vestigial 

 structures selected for discussion. There is a brief 

 chapter on the brain, which can scarcely be considered 

 adequate when it is remembered that it is the organ 

 which has played the chief part in making man what 

 he is. 



The closing chapters arc perhaps most useful to the 

 zoological reader. They deal with man's nearest 

 NO. 2176, VOL. 87] 



relatives, the primates, fossil-man and Pithecan- 

 thropus. 



It is gratifying to find that Prof. Leche lends the 

 weight of his support to the view, first set forth in 

 Nature in the year 1907, that Tarsius is the slightly 

 specialised living representative of a very primitive 

 group of primates, from which the lemurs and the 

 apes were derived by specialisation along divergent 

 lines; that in this sense Tarsius is the connecting link 

 between these two suborders, because it is the least 

 modified descendant of the common parents of all 

 three suborders of primates. 



There is a very useful summary of the circumstances 

 of the discovery of the remains of Palaeolithic man 

 and Pithecanthropus, with an unbiassed account of 

 the nature and significance of these much-discussed 

 relics of fossil-man. In the chapters dealing with this 

 subject he follows Schwalbe in most matters, and 

 describes the recent trend of opinion on the Continent 

 in reference to Pakeolithic man, without committing 

 himself, however, to any of the extreme views that 

 are so much in evidence at the present time. 



The volume closes with a brief statement in refer- 

 ence to certain points in the anatomy of modern man 

 that have some wider significance of racial or 

 sociological importance. 



Prof. Leche's book can be heartily recommended as 

 a calm and dispassionate summary of the present state 

 of our knowledge of the structure of man, as it is 

 interpreted by comparative anatomy. G. E. S. 



GEOLOGY AND BUILDING STONES. 



(1) The Geology of Building Stones. By J. Allen 

 Howe. Pp. viii + 455. (London: E. Arnold, 1910.) 

 Price ys. 6d. net. 



(2) British and Foreign Building Stones: a Descrip- 

 tive Catalogue of the Specimens in the Sedgwick 

 Museum, Cambridge. By John Watson. Pp. viii + 

 484. (Cambridge: University Press, 191 1.) Price 

 3s. net. 



(1) T^HERE has long been a demand for a book 

 1 such as that now produced by Mr. Howe. It 

 would be well for all architects, and also engineers, 

 to go through some short course of geological train- 

 ing, leading up to the understanding of a geological 

 map. Mr. Howe has to meet those cases where no 

 preliminary work has been possible, and he describes 

 in a clear manner the essential characters of rock- 

 forming minerals. Quaintly, but properly enough, he 

 includes ice, the mineral most utilised by the Eskimo. 

 Knowing as he docs the utility of the microscope, he 

 introduces extinction angles in the table of the fel- 

 spars on p. 20, but these are left unexplained, and 

 the variation in the angle between the cleavages would 

 surely be more interesting to the beginner. Thin 

 sections of typical rocks are well illustrated in the 

 later pages. The work of Dr. Flett, Mr. Lovegrove, 

 and the author, has probably introduced the micro- 

 scope to many "practical" men with good effect. 



The classification of rocks employed is commend- 

 ably simple. Trachyte seems to have slipped out of 

 the table on p. 43, as a parallel with rhyolite and 

 andesite, though it is described on p. 103. Mr. Howe 



