January 27, 1910] 



NATURE 



increase in bulk. Additions have been made to the 

 accounts of nearly every system of organs, and the 

 verbal descriptions supplemented by the inclusion of 

 nearly one hundred new text-figures. The new figures 

 illustrating the skulls, so coloured as to distinguish 

 bone from cartilage, are very effective, and those of 

 Petromyzon, Lacerta, Crocodilus, and Chelone will 

 be found especially useful ; indeed, it is a pity that a 

 few more laboratory types (such as Hatteria, and some 

 additional birds and mammals) were not included at 

 the same time. The valuable literature-list — a most 

 excellent feature of this book — has also of necessity 

 been much enlarged. 



The account of the nervous system shows a marked 

 advance on that of the earlier editions. The descrip- 

 tion of the internal structure of the brain embodies 

 some of the important results obtained in recent years 

 by Edinger, Sterzi, Elliot Smith, Johnston, and other 

 workers in this branch of anatomy. There is also 

 included a more thorough exposition of the modern 

 component theory of the cranial nerves, though we 

 are of opinion that the sections treating of this sub- 

 ject, and of the primitive segmentation of the head, 

 might with advantage have been still more expanded, 

 both as regards the facts and their theoretical inter- 

 pretation. The questions, for example, as to the 

 alleged serial homology between ordinary eyes and the 

 paired pineal organs, the primitive sensory nature of 

 the epibranchial placodes (referred to on p. 331) and 

 their possible connection with the eye and the nose, 

 the late origin and consequent non-homology of the 

 acustico-lateral system of nerves with the spinal nerves, 

 the secondary nature of the segmental arrangement of 

 the lateral-line sense-organs, the curious situation of 

 the supposed gustatory organs in the external skin of 

 certain teleosts and their innervation by the visceral 

 sensory lateralis accessorius nerve, are all of intense 

 interest, and worthy of a brief discussion in a book 

 dealing with the fundamentals of vertebrate morpho- 

 logy. The chief results of the large amount of work 

 recentU' pursued in connection with the gas-bladder of 

 fishes have also been incorporated in the revised account 

 of this subject, though we cannot agree with the un- 

 hesitating adoption of the Reis-Niisbaum idea that 

 the gas contents of the bladder are the product of 

 the chemical decomposition of the substance of the 

 gland-cells; in our opinion Jaeger's view, that the 

 oxygen and other gases are derived directly from the 

 blood and are merely pumped into the bladder cavity 

 by the gland-cells, seems much more feasible. Among 

 other sections of the book which have been consider- 

 ably altered and extended are those relating to the 

 morphology of the sternal skeleton, the phylogeny of 

 the limb skeleton, the structure of the mammalian 

 lung, the urinogenital apparatus of bony fish, and 

 the male copulatory organs of the chief vertebrate 

 groups. 



Concerning what we venture to consider omissions 

 in the book, we must confess that we should like to 

 have seen, among other things, a complete account 

 of the recent work of Osborn, Broom, and others on 

 the Thcriodont reptiles, and of the origin of the Mam- 

 malia from this ancient group, a subject of intense 

 interest to comparative anatomists and one which 

 NO. 2100, VOL. 82] 



has now been worked out in such complete detail 

 that we can trace in these fossil reptilian skeletons 

 the evolution of almost every bone in the mamma- 

 lian skeleton. Again, the subject of the minute 

 structure of fish-scales, to which Goodrich has recently 

 directed attention, is quite untouched in the present 

 work, though the facts are most striking, both from 

 the standpoints of pure morphology and classification. 

 In saying that these subjects are omissions, and 

 thereby implying that in our opinion they should 

 have been included, we are not unmindful that the 

 size of the book must be kept within reasonable 

 limits; we would only suggest that succinct accounts 

 of the subjects just named and those before referred 

 to are far more suitable for inclusion than descrip- 

 tions and figures, e.g. of the external form of the ear, 

 of the development of the cement organ of Polypterus, 

 of the layers of the retina, and other similar topics 

 which, though also worthy of mention, are of rela- 

 tivelv less moment. 



We may point out in conclusion that to the best of 

 our belief the common text-book statement (p. 642) 

 that the at-first paired umbilical (allantoic or hypo- 

 gastric) veins are homologous with the epigastric 

 veins of Amphibia and the lateral veins of Elasmo- 

 branchs has been disproved by Beddard : the two sets 

 of veins are quite distinct. 



A standard book like the present, and especially 

 this last superb edition, is in no need of recommenda- 

 tion, and our recognition of this is a sufficient apology 

 for the large proportion of criticism contained in the 

 preceding remarks. W. N. F. W. 



THREE TEXT-BOOKS OF PRACTICAL 



CHEMISTRY. 



(i) A Course of Practical Chemistry Suitable for Public 



Schools. By A. Beresford Ryley. Pp. viii + 156. 



(London : J. and A. Churchill, 1909.) Price 45. 6d. 



net. 

 (2'! Introduction to Practical Chemistry, for Medical, 



Dental, and General Students. By A. M. Kellas. 



Pp. viii + 262. (London: Henry Frowde, and 



Hodder and Stoughton, 1909.) Price 35. 6d. net. 

 (3) First Stage Inorganic Chemistry (Practical). For 



the First Stage Examination of the Board of 



Education (South Kensington). Revised Edition. 



By H. W. Bausor. Pp. iii+85. (London: W. B. 



Clive, LIniversity Tutorial Press, Ltd., 1909.) 



Price li. 



A S a general rule, the teacher of practical chemistry 

 /v yields sooner or later to the apparently irresistible 

 temptation of writing a text-book for the use of 

 students attending his classes. The consequent 

 excessive multiplication of elementary treatises is, in 

 the main, deplorable, although the contents of some 

 of these publications afford an interesting indication 

 of the trend of contemporaneous science teaching. 



(i) The course of practical chemistry suitable for 

 public schools is of special significance from this point 

 of view, inasmuch as the author refers to his procedure 

 as a retrogression from the heuristic method, a system 

 which he dismisses as " ideal, but quite impracticable 

 in the larger classes of public schools." This course 



