BOOK REVIEWS 139 



The difficulty encountered in the production of such a book 

 is that of keeping it up to date since no other biological subject 

 is advancing with such rapidity as is the study of heredity. It 

 is to be hoped that a revised edition of this excellent' book will 

 be prepared. R. W. H. 

 First Principles of Heredity, By S. Herbert. Pp. xiv+346. 



The Macmillan Company for A & C Block, London $2.00 

 Dynamic Evolution, By Casper L. Redfield. Pp. xi + 210. 



G. P. Putnam's Sons. $1.50 

 Heredity and Environment. By Edwin G. Conklin. Pp. xiv + 



533. Princeton University Press. $2.00 

 The Mechanism of Mendelian Heredity. By T. H. Morgan, 



A. H. Sturtevant, H. J. Muller, and C. B. Bridges. Pp. xiii 



+ 262. Henry Holt & Company. $3.00. 



The titles of these books seem quite diverse, and yet all are 

 treating the subject of evolution and some of the problems that 

 are fundamental to it. The First Principles of Heredity presents 

 the outline of cosmic evolution briefly, then takes up the evolu- 

 tion of the earth, but devotes the major part of its subject matter 

 to the discussion of the evolution of life. The earlier chapters 

 on the evidence from morphology, embryology, geographical dis- 

 tribution, Lamarckism and Darwinism, are very similar to those 

 of Romanes. The book will be much appreciated, however, for 

 its clear presentation of neo-Lamarckism, orthogenesis, and its 

 discussion of mental and moral evolution. The latter part of 

 the book deals with the evolution of Society. It is evident, then 

 that the book is quite comprehensive. A valuable part of it is 

 the citation of literature in connection with each chapter. The 

 author is apparently reasonably familiar with the modern liter- 

 ature of the subject, and refers to much of the valuable work that 

 is under way both in England and on the continent. He does 

 not seem to be impressed with the work on experimental evolu- 

 tion that is being done in this country. One would expect to 

 find reference to such work as that of Morgan, Tower, Shull, 

 Mac Dougal, and others, but no references are made to their 

 investigations. 



Dynamic Evolution, by Redfield, is an attempt to show that 

 the energy . developed in organs through functioning is cumula- 

 tive and is transmitted to succeeding generations. The author 

 says that speed in the case of the trotter, is improved by training 



