20 



Mrs. Green's book also bring out many interesting things con- 

 cerning the "folklore" of trees, a subject on which much remains 

 to be written. In addition, this being a book on trees of the Southern 

 States, many species are included with which we at the north are 

 less familiar, such as the Chinaberry, the Crape Myrtle, the Lob- 

 lolly Bay, the Silver Bell and Snowdrop trees (Halesia) and the 

 Sweetleaf, besides the southern pines. In addition, of course, most 

 of the trees of the north are described. 



Mr. J. S. Holmes, State Forester of North Carolina, who, I 

 am proud to say, was once a pupil of mine at the Yale School of 

 Forestry, has written a splendid foreword. The illustrations, of 

 which there are many throughout the book, are admirable. I do 

 not see how they could be improved. It is, altogether a beautiful 

 book, and it is a pleasure to have the opportunity of reviewing it. 



Two New Books on Genetics 



R. C. Benedict 



Sturtevant and Beadle, An Introduction to Genetics* 



"Genetics is a quantitative subject. It deals with ratios, with 

 measurements, and with geometrical relationships of chromosomes. 

 UnHke most sciences which are based largely on mathematics, it 

 makes use of its own system of units." The preceding, the opening 

 sentence of the Preface of Sturtevant and Beadle's new text, "An 

 introduction to genetics," furnishes the keynote for the volume. 



The book is significant in a number of ways. First, it is of 

 interest to have a text-book treatment in formal genetics of which 

 one of the authors was a chief collaborator with Morgan in estab- 

 lishing modern genetics. Second, it is important to have the point 

 of view of genetics as a quantitative subject rigorously carried 

 out in a book for class use. Third, the text is valuable for the 

 recency and comprehensiveness of its factual data, and its discus- 

 sion of their implications and applications. Recent advances in 

 cytology during the past few years seem to have led to an enlarged 

 understanding of the mechanics and significance of mitosis and 



* An introduction to genetics. Sturtevant, A. H., and Beadle, G. W. 

 G. W. Saunders. 1936. $3.25. 



