78 Scientific Intelligence, 



The structure and development of the germ cells, their union 

 in fertilization; the sex-determining chromosomes and their 

 behavior in the life cycles of organisms with alternate sexual 

 and parthenogenetic stages ; the cleavage of the egg and the 

 differentiation of the resulting cells into the tissues of the body ; 

 the cytological explanation of variations and evolutionary muta- 

 tions ; and the physical explanation of sterility are the principal 

 subjects treated. The book is concisely written and illustrated 

 with text-figures of the highest excellence. w. r. c. 



7. General Botany for Universities and Colleges; by Hiram 

 D. Densmore, Professor of Botanv at Beloit College. Pp. xii, 

 459, with 289 figures in text. Boston, 1920 (Ginn & Com- 

 pany). — The author's viewpoint in this excellent addition to the 

 list of text books of botany is biological throughout. In the first 

 part the higher seed plants are considered with respect to their 

 environment, structure and physiology; in the second part the 

 great plant groups are concisely but clearly and accurately 

 treated ; in the third part the representative families and species 

 of the spring flora in the northern United States are taken up, 

 and a brief account of plant associations is included. So far as 

 possible the purely scientific portions of the text are logically 

 connected with those aspects of plant biology which are of imme- 

 diate human interest. Much emphasis is therefore laid upon the 

 phenomena connected with hybridization, breeding and evolu- 

 tion, and the significant processes connected with cell and nuclear 

 divisions are more fully treated than in most elementary works. 

 The thoroughly modern discussion of plant anatomy is likewise 

 a noteworthy feature. As a basis for a year's college course in 

 general botany the new text seems admirably adapted. 



a. w. E. 



8. Problems in Botany; by W. L. Eikenberry, Associate Pro- 

 fessor of Education, University of Kansas. Pp. xii, 145. Bos- 

 ton, 1919 (Ginn & Company). — The purpose of this labora- 

 tory manual is to place before high-school pupils a series of 

 problems dealing with plant activities, their relation to human 

 interests being emphasized throughout. References to Bergen 

 and Caldwell's text-books are given in connection with each of 

 the 118 exercises. Among the subjects treated the following are 

 perhaps the most important : plants and water, nutrition, repro- 

 duction and propagation, relation to environment, relation of 

 simple plants to man's life and industries, and plant industries. 

 Each problem is definitely stated, clear directions are given for 

 studying the material recommended, and the pupils are expected 

 to draw their own conclusions from their experiments and obser- 

 vations, a. w. E. 



9. Joseph Dalton Hooker (Pioneers of Progress, Men of 

 Science); by F. 0. Bower, Regius Professor of Botany in the 

 University of Glasgow. Pp. 59, with frontispiece. London, 

 1919 (Society for Promoting Christian Knowledge). — The great 

 importance of the work done by Sir Joseph Hooker (1817-1911), 



