REVIEWS 169 



hands of every student of zoology, and is the standard practical textbook through- 

 out the laboratories of Great Britain. The fact that the work is in its eighth 

 edition is in itself sufficient guarantee of its general utility. There have been 

 included in this edition a useful note on the Trypanosome of the Dogfish, and 

 diagrams of the ventral aspect and a median longitudinal section of the skull of 

 the dog. C H. O'D. 



Civic Biology. A Textbook of Problems, Local and National, that can be solved 

 only by Civic Co-operation. By C. F. HODGE, Ph.D., and J. DAWSON, 

 Ph.D. [Pp. viii + 381, with 2 coloured plates and 168 figures.] (London 

 and New York : Ginn & Co., 1918. Price ys. net.) 



The sub-title of this useful little book indicates very clearly its contents. It is 

 prepared for use in schools and training colleges, and forms a course in biology 

 for older scholars. The particular problems that are studied are those that 

 concern the community as a whole, and can be dealt with only by co operative 

 action, either voluntarily or by means of legislation. This, however, implies an 

 appreciation of the problems involved and an intelligent grasp of the means of 

 studying and dealing with them. The aim of the book is " to make it possible 

 for every one to understand what these [biological forces] are, for good or ill, and 

 how to do his part for his own good and that of the community." Certainly any 

 one who had the good fortune to have worked through a course on the lines 

 suggested by this book would have obtained not only what was aimed at but also 

 a very sound general training in field biology. 



The subjects treated — insect pests, fungoid diseases, rat plagues, etc., on the 

 one hand, and the preservation of useful or attractive animals on the other — are 

 illustrated by examples chosen from the United States. The actual species and 

 their life histories therefore would not be the same in Great Britain, at any rate in 

 most cases, but a course drawn up on similar lines dealing with local problems 

 would be an excellent finish to the "Nature study" lessons now given. In fact, 

 in agricultural districts in particular it might replace the so-called " Nature study" 

 with considerable gain to the biological training and future effectiveness of the 

 student as a member of the community. It is a book to be commended. 



C. H. O'D. 

 GENETICS 



Genetics in Relation to Agriculture. By Ernest Brown Babcock, Pro- 

 fessor of Genetics, University of California, and Roy Elwood Clausen, 

 Assistant Professor of Genetics, University of California. [Pp. xx -f 675.] 

 (New York : McGraw-Hill Book Company ; London : Hill Publishing Co., 

 1918. Price $3.50 net.) 

 This work is really considerably more than its title indicates. It is not merely 

 an account of genetics applied to agriculture ; it is an authoritative textbook 

 on the facts and principles of genetics as well as on the application of these 

 to plant and animal breeding. 



The book is divided into three parts : fundamentals, plant breeding, and 

 animal breeding. The first part deals entirely with the pure science of genetics, 

 and constitutes a text-book of the subject. While excellent works exist which 

 deal with parts or certain aspects of the subject the present account covers 

 the whole ground of the study of heredity and allied problems. The methods 

 of genetics are, according to the authors, four in number. These are (1) the 

 method of observation, of which Charles Darwin's work is the most brilliant 

 example, (2) the method of experimental breeding to which we owe the great 



