172 BOOKS AND CURRENT LITERATURE 



Chapter VI, on hybridization, includes many things. There are 

 discussions of natural selection, limits of crossing, natural hybrids, 

 artificial hybrids, effects of inbreeding and crossbreeding, and graft 

 hybrids. As indicated, it is a dip here and a dip there into some of the 

 most important questions of plant breeding, with hardly an adequate 

 treatment of each phase. Heredity, in the next chapter of sixty pages, 

 is dealt with more ably, though one may be skeptical as to the desira- 

 bility of continuing to use the coefficient of correlation, a measure of 

 somatic resemblance, as a test of heredity after the confusion it has 

 led to through the efforts of the English biometrical school. Further- 

 more, the reviewer feels that the beginning student may get an errone- 

 ous idea of Mendelian inheritance, or rather of the meaning of the 

 Mendelian notation, from the author's method of treating the subject. 

 Presumably, the very literal interpretation of a plant as a unit char- 

 acter mosaic is due to the need to compress a large amount of material 

 into a small space, but it might work considerable harm. 



Perhaps the best chapter in the volume is that on How Domestic 

 Varieties Originate (Chapter VIII). It contains much historical 

 matter that would be difficult to obtain elsewhere. 



The remainder of the book is much like the fourth edition. It 

 deals with the technique of crossing and "the forward movement in 

 plant breeding" as illustrated by practical work in various parts of 

 the world. 



There are five appendices, including a glossary, a list of plant breed- 

 ing books, a bibliography brought up to date (from 1905, the year of 

 the last citations in the fourth edition), and a series of laboratory 

 exercises. The bibliography is especially valuable, though one notices 

 that many important foreign publications are omitted. The defini- 

 tions given in the glossary for such terms as allelomorph, dominant 

 character, factor hypothesis, and segregation, will hardly be accepted 

 by geneticists. — E. M. East. 



Phototropism (?) of Urediniospore Germ-Tubes. — A short paper 

 by Fromme 1 presents the newly-demonstrated fact that urediniospores 

 of Puccinia rhamni, and their young germ-tubes, are sensitive to one- 

 sided illumination. The large majority of these spores, when germi- 

 nating with one-sided lighting, protrude the germ-tube from a spire on 

 the shaded side. If a tube protrudes from the more strongly lighted 



1 Frooime, F. D., Negative heliotropism of urediniospore germ-tubes. Amer. 

 Jour. Bot. 2: 82-85. 1915. 



