REVIEWS 725 



be found in the standard works upon these subjects, this book will be of great 

 service. It is written throughout in a style which will claim the interest of the 

 reader. 



The first chapter, which deals with Weismannism and Darwinism, is very 

 clearly written and puts forth the views of these two great scientists with a 

 simplicity which cannot fail to please, at the same time with a vividness which 

 will give the reader a good grasp of the fundamental principles. 



The chapter on Mendelism is very good so far as it goes but it would have 

 been better had the author devoted some attention to the discussion of the 

 results obtained when dealing with pairs of allelomorphic characters. His 

 amended Mendelian scheme is ingenious and we have not been able to detect 

 any glaring flaws in his argument. In it he gives the results of the crosses in 

 terms of the zygote and puts forth the view that when pure tall peas and pure 

 dwarf peas are crossed zygotes of three kinds appear" in F,, viz. (i) One quarter 

 having tallness pure both in the propagative and the somatic part. (2) One quarter 

 having dwarfness pure in the propagative part and tallness in the somatic part. 

 (3) The remaining half with tallness and dwarfness present in the propagative 

 part and only tallness in the somatic part. Hence in Fj the zygotes are all pure 

 tails in the somatic part and the plants are therefore all tails. The quarter with 

 dwarfness pure in the propagative part produce pure dwarfs in F., ; the quarter 

 with tallness pure in the propagative part breed pure to tallness and the remaining 

 half behave as in F,. 



The author objects to the use of the terms dominant and recessive and 

 substitutes for them the terms "first character" and " second character." This 

 suggestion appears to us to be very good and deserving of serious consideration 

 by Mendelian workers. 



He gives veiy good accounts of Biometry, AInemism and Mutation and in 

 his Intrinsic Theory of Variation attaches great importance to the reducing 

 division of the chromosomes on the formation of the gametes, urging that when 

 the primitive germ cells are undergoing mitosis the " determinants of the unit 

 characters in them are being arranged according to the Law of Probability " and 

 hence that this is a step in the process of producing variation. 



The chapter on Heredity is remarkably good but his definition of it is somewhat 

 lax and it would have been much better if the author had stated that heredity was 

 merely a convenient term for expressing the genetic relation between successive 

 generations. 



For the rest of the book we have nothing but praise ; the chapters on a Modern 

 Observation Hive and the Evolution of the Honey Bee are remarkably well 

 written and extremely interesting. The book is full of interesting and useful 

 information and should take a place in the front rank of the semi-popular works 

 of this nature. 



J. W. Chaloner. 



Arnold's Geological Series : A Textbook of Geology. By Philip Lake, M.A., 

 F.G.S., and R. H. Rastall, M.A., F.G.S. [Pp. xvi + 494.] (London : 

 Edward Arnold, 1910. Price 16s. net.) 



It is some years since a new textbook of geology has appeared and the present 

 publication, which is the work of two well-known Cambridge teachers, will be 

 examined with interest. In the editor's preface Dr. Marr tells us that physical 

 geology and stratigraphy, the two subjects with which the work deals, should be 



