21 



meiosis ; these are discussed in this text. While the Sturtevant and 

 Beadle is relatively short and compact, readers will not find that 

 matters of general interest have been omitted ; for example, there 

 are twenty-three index references to human inheritance. Evolu- 

 tion is indexed only once, but the experimental bases upon which 

 evolutionary changes are predicated, gene differences, polyploidy, 

 etc., receive careful attention. One whole chapter is devoted to 

 "species differences." 



In line with its emphasis on the mathematical aspects of the 

 subjects, most of the chapters end with a series of selected prob- 

 lems for the student. The illustrations, relatively few in number, 

 bear chiefly on the critical features of chromosome structure and 

 behavior, and on differences in color and structure in Drosophila.. 

 An appendix contains an explanation of the mathematics of cer- 

 tain special problems. There is an extensive bibliography, and a 

 brief but discriminating historical survey of the steps by which 

 the cytogenetic basis of the gene concept of heredity was reached. 



It appears certain that this text will be found essential for 

 Hbrary reference, for maturer students of the subject, and for 

 teachers in the field of biology. Its value as a specific text for class 

 use will depend upon the level of the biological curriculum at 

 which work in genetics is given, and the preliminary training set 

 up as a prerequisite. Courses involving introduction to the prin- 

 ciples of genetics are given through all the years of college under- 

 graduate work and also as part of high school biology. Among the 

 several textbooks by American authors, there is considerable range 

 in difficulty and design ; some like the Walter, the Shull, and the 

 Snyder, are adapted for the more "popular" courses of the lower 

 undergraduate years ; others like the Castle, the Babcock and 

 Clausen, and the Sinnott and Dunn, are better fitted for advanced 

 undergraduate or graduate courses. The Sturtevant and Beadle 

 belongs clearly in the latter group. 



Waddington, An Introduction to Modern Genetics* 



The thesis of this text by Waddington, "An introduction to 

 modern genetics," is furnished by Bateson's original definition of 

 the word, genetics, as quoted in the Introduction ; as the science 



* An introduction to modern genetics. Waddington, C. H. ^Macmillan. 

 1939. $4.00 



