Zoology and Botany. 465 



9. Heredity and Evolution in Plants; by C. Stuart Gager, 

 Director of the Brooklyn Botanic Garden. Pp. v, 265, with 112 

 text-figures. Philadelphia, 1920 (P. Blakiston's Son & Co.). 

 — The author liere gives us a revision of certain chapters in 

 his Fundamentals of Botany, published in 1916. These chapters 

 furnished a concise but very clear treatment of the various 

 theories connected with the heredity and evolution of plants, 

 strong emphasis being laid upon recent experimental methods 

 of investigation. Two chapters, not in the earlier work, deal 

 with geographical distribution of plants and with the great 

 taxonomic groups into which plants have been divided. A val- 

 uable bibliography concludes the volume. a. v^. e. 



10. Diseases of Economic Plants; by F. L. Stevens and J. G. 

 Hall; revised edition by F. L. Stevens. Pp. vii, 507, with 237 

 text-figures. New York, 1921 (The Macmillan Company). — The 

 first edition of the present work was published in 1910. The 

 revised edition is designed to meet the special needs of college 

 students, and a part of the revision consists in the rearrange- 

 ment of the subject matter. Many diseases of major importance, 

 liowever, have come into prominence during the past ten years 

 and descriptions of these naturally find a place in the new 

 volume. There are likewise a number of new illustrations, and 

 certain modifications of treatment are recommended. With but 

 few exceptions the diseases discussed are these caused by fungous 

 parasites. a. w. e. 



11. The Nature-Study of Plants in Theory and Practice for 

 the HoMy -Botanist; by Thomas Alfred Dymes. Pp. xviii, 173, 

 with frontispiece, 5 plates and 51 text-figures. London, 1920 

 (Society for Promoting Christian Knowledge). — The subject- 

 matter of this attractive little book is divided into two parts, the 

 first entitled ' ' Theory ' ' and the second ' ' Practice. ' ' In the first 

 part the scope of nature-study is defined, and the various "fac- 

 tors of life ' ' are discussed with reference to the ' ' life and preser- 

 vation of the individual" and also with reference to the "pres- 

 ervation of the race." In the second part a common British 

 plant, the Herb Robert (which is likewise common in North 

 America), is thoroughly considered in its numerous aspects, the 

 life-history being followed step by step from the germination of 

 seed to the dispersal of the ripened fruitlets. The intensive 

 study of a single species, which is here recommended, meets the 

 approval of Professor F. E. "Weiss, of Manchester, who has sup- 

 plied an introductory note to the volume. a. w. e. 



12. The -Chemistry of Plant Life; by Roscoe W. Thatcher. 

 (McGraw-Hill Book Co.), New York. Pp. xi, 268.— This is a 

 text-book of biochemistry written for the use of students of bot- 

 any and drawing its illustrations from the facts and problems of 

 the plant kingdom. The volume presupposes training in inor- 

 ganic and organic chemistry on the part of the reader. It deals 

 with composition rather than the dynamics of living matter, but 



