80 



In discussing Segregation and Dominance, Old Types and New, 

 and Blending Inheritance, the author is fully committed to the 

 Mendelian interpretation. Characters are treated as inde- 

 pendent units which "segregate out as if independent of each 

 other," and the factor hypothesis is given for its full assumed 

 value in the explanation of heredity. The assumption of an 

 increased number of "duplicate determiners" which explain all 

 phenomena of blending inheritance is given as "strictly cases of 

 Mendelian dominance and segregation." 



It would seem that even a popular book of this sort should 

 present the facts concerning incomplete segregation, the evidence 

 for the modification of the so-called unit-characters by selection 

 and the various difficulties and inadequacies of the Mendelian 

 notation. Aside from this, the selection of experimental data 

 is well made and is representative of the lines of the experi- 

 mental research of the past decade. 



There is at present no other book that attempts to cover in a 

 semi-popular way so much that pertains to heredity. The 

 volume is an introduction to the study of heredity presented 

 from what may be called the Mendelian viewpoint. 



A. B. Stout 



"Heredity of a Maize Variation" is the title of Bulletin No. 

 272 written by G. N. Collins and issued in January by the Bureau 

 of Plant Industry of the United States Department of Agri- 

 culture. 



This paper reports the appearance of a single white ear of 

 maize as an "albinistic mutation" in a strain of pure yellow corn 

 and gives an account of various studies on the heredity of this 

 ear. Three xenia generations were secured by self fertilization, 

 and crosses between certain of these and two types of white corn 

 are reported. In all of these the endosperm characters were 

 studied and the results tabulated and expressed in ratios. 



The results viewed in a general way give a fair agreement with 

 the ratios of Mendelian expectation, but upon more careful 

 analysis the author finds that in certain cases either a mono- 

 hybrid or a dihybrid ratio might apply, depending on the grade of 

 classification. 



