414 NATURAL SCIENCE. j ONE( 



third month of fetal life, subsequent increase in size depending upon 

 the enlargement of already formed cells. It would thus appear that 

 environment and training have little or no influence in producing new 

 cells, but produce their result by perfecting the development and 

 inter-relationship of pre-existing materials. These considerations are 

 employed with some success in explaining the phenomena of the 

 growth of the brain, and the differences in the brain-weights of the 

 sexes and the different races of mankind. The architecture of the 

 nervous system, the arrangement of its structural elements into 

 systems, and the development of the latter, form the subject of 

 several chapters, which conclude the anatomical and larger section of 

 the book. 



The later chapters deal with function and its development, 

 treating them, not from the point of view of the text-book of physiology, 

 but rather from the psychological side. This part of the book is fully 

 as well written and suggestive as the preceding, and leads up, after a 

 chapter on " fatigue " and one on "old age," to the consideration of the 

 education of the nervous system. It may be regretted that more space 

 is not devoted to this last subject, since it is the one to which the 

 whole book has led up, and further, that it is dealt with in so general a 

 manner. The value of the book to the educationalist would have 

 been considerably enhanced by a chapter on the practical outcome 

 of the considerations which have been enforced. Nevertheless, the 

 work will be of much interest to those teachers who have sufficient 

 knowledge to master its technical details, while the psychologist and 

 physician will find it a well-written and valuable resume of neurological 

 science. 



Milk for German Babes. 



Grundriss der Krystallographie. By G. Linck. 8vo, pp. vi., 253, with two 

 coloured plates and numerous figures. Jena: G. Fischer, 1896. Price 9 marks. 



This is a text-book intended for young students and beginners, but 

 we doubt whether it will be a favourite book with those for whom it 

 is intended, unless the German student is a hardier person than we 

 imagine. Too much information is squeezed into too small a space ; 

 an attempt is even made to give an intelligible account of the large 

 subject of Chemical Crystallography in the last eleven pages, after 

 the geometry and physics of the subject have been packed into the 

 first 230 pages. On the very first page, where it is merely stated 

 that tourmaline becomes electrified by friction, Professor Linck 

 thinks it necessary to insert after the word " Turmalin " 



(n Si a C3 B 6 Al 16 R 4 H 8 + n Si„ O m B 6 Al 10 Mg 12 H 6 ). 

 This we quote in order to illustrate, not so much the process of 

 squeezing into too small a space, as the superfluity of information. 



In some matters the author is fully up to date, e.g., in the 

 reference of the optical characters of crystals to the geometry of the 

 Indicatrix ; in others he is lamentably behind the times, as in the 

 retention of the Naumannian system of notation. It is true that the 

 Millerian symbols are also given, but we had hoped that, since the 

 publication of the classic works of Mallard, Liebisch and Groth, no 

 text-book would introduce the more cumbersome notation except as a 

 thing of historical interest. The diagrammatic representation of the 

 various types of symmetry by means of shaded areas does not appeal 

 to the eye like perspective figures, or like stereographic projections. 

 That the projection on a sphere should not be even mentioned is an 

 omission which is almost unpardonable in a modern text-book of 

 crystallography. 



