!8 9 6. SOME NEW BOOKS. 413 



divisions of the fishes. The Palaeichthyes of Gunther may now be 

 definitely buried, since A. S. Woodward has provided for us a com- 

 plete summary of the Palaeozoic and Mesozoic fishes, and no one who 

 has followed the progress of ichthyological studies can conceal from 

 himself the fact that the further recognition of the existence of the 

 ganoids is seriously endangered now that the three best authorities on 

 fossil fishes, Cope, Traquair, and A. S. Woodward, have pronounced 

 against it. The families established by Woodward in the third 

 volume are all defined and characterised with such care that they can, 

 indeed, for the most part, be little affected by the varying views on 

 classification. They include closely-related forms and represent 

 natural stages in the course of development in this large class of 

 vertebrates. Woodward's catalogue deserves the highest praise, not 

 only for its completeness, but also for its critical acumen and the 

 incomparable mode of handling of the material with which the author 

 deals. When completed, this work will form the basis for all 

 palaeichthyological researches for the next decades. The beautiful 

 restorations of eight Mesozoic genera in the text ought soon to banish 

 from text-books the familiar figures of Agassiz. Like the eighteen 

 lithographic plates, they are the work of the skilful and trained pencil 

 of Miss Gertrude Woodward, and undoubtedly rank among the best 

 pictorial representations of fossil fishes. Karl von Zittel. 



The Brain and " Brains." 



The Growth of the Brain ; A Study of the Nervous System in Relation to 

 Education. By Henry H. Donaldson, Professor of Neurology in the University 

 of Chicago. Contemporary Science Series. Pp. 369. London : Walter Scott, 

 Ltd., 1895. Price 3s. 6d. 



This excellent little book covers a held even wider than its title 

 implies. Considerable advances have been made in recent years in 

 our knowledge of the comparative anatomy, the minute structure and 

 development, and the physiology, both human and comparative, of 

 the central nervous system. Psychology has been pursued from the 

 experimental rather than the metaphysical side, and education has 

 become a science as well as an art. Professor Donaldson has collected 

 a large body of facts and statistics from all these departments of 

 knowledge, and has so marshalled them as to illustrate very fully the 

 development of the central nervous system and the physiology of 

 education. 



The freshness of the book lies, not so much in new and 

 original matter, of which there is little, but in the treatment and 

 grouping of facts already established, and in the logical deductions 

 drawn from them. The introductory chapters deal with the facts of 

 growth in general, and are illustrated by numerous tables and curves. 

 The absolute weights of the central nervous system and its chief 

 component parts are then discussed from various points of view, after 

 which its curves of growth are given, showing that by the seventh 

 year, practically before formal education has begun, the brain has 

 already reached nearly to its adult weight. The influence of brain- 

 weight as a factor in determining intelligence receives critical 

 discussion. The minute structure and development of the nervous 

 system is next considered, and particular attention is devoted to the 

 relative volumes of the nerve-cells and their processes in comparison 

 with the embryonic germinal cells from which they arise. From the 

 best statistics available (Meynert, His, and others) it is deduced that 

 there is no need for the production of new nerve-elements after the 



