232 NATURE STUDY REVIEW [9:7— Oct., 1913 



A few errors need correction in the revision: the diagram on 

 page 23 shows only one generation of spermatocytes, and a division 

 of the spermatids. There should be two generations of spermato- 

 cytes corresponding to the two of the oocytes and the spermatids 

 transform to spermatozoa without division. Page 24 has a 

 corresponding mistatement that the number of chromosomes 

 "remains constant in each germ cell respectively until the division 

 of the spermatids into spermatazoa." Spermatids do not divide 

 to form spermatazoa, and the number of chromosomes is reduced to 

 one-half the somatic number when they appear in the spermato- 

 cyte of the first order preparatory to its division. These two are 

 the most glaring errors the reviewer has noted. On page 123 is a 

 typographical error, the date of the appearance of Mendel's results 

 given as 1886, should be 1866, as indicated in the footnote. 



Mendel's Principles of Heredity, by W. Bateson. Pages XIV 

 plus 413. Cambridge University Press, 3d edition. Price $3.50. 

 G. P. Putnam's Sons in this country. 



It speaks well for this book that a third impression is necessary 

 so soon. Professor Bateson has been one of the most enthusiastic 

 English investigators and he himself has added materially to our 

 knowledge of Mendel's law and its limitations. He has taken as 

 his chief materials for investigation the color of flowers, and much 

 of the material in this book is drawn from his own work. There is 

 an historical introductory chapter; then a careful presentation of 

 Mendel's law, with a review of practically all of the work that has 

 been accomplished in confirmation and extension of the law. 

 Chapter g is on gametic coupling. Chapter 10 treats of heredity 

 and sex. Chapter 12 discusses the evidence of Mendelian inheri- 

 tance in man. Chapter 14 is especially valuable; it is on the mis- 

 cellaneous exceptional and unconformable phenomena. Thus far 

 the book does not differ materially from the earlier edition, but 

 there is added an appendix in which there is given in the order of 

 treatment in the body of the book a series of summaries of the 

 work accomplished since the second edition bearing upon the 

 questions discussed. The bibliographical sketch of Mendel 

 together with a reproduction of Mendel's original paper, translated, 

 makes the book particularly valuable. There is also given a full 

 bibliography, pages 385 to 402. This is a somewhat more scientific 

 presentation of the subject than Walter's treatment, reviewed 

 above, yet the style is clear so that it makes fascinating reading. 



