416 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



changed conditions of life. The authors do not appear to us to lay 

 enough stress upon this, the obvious and primary cause of all variations. 

 As Dr. Weismann acknowledges, " We are driven to the conclusion that 

 the ultimate origin of hereditary individual differences lies in the direct 

 action of external influences upon the organism " (" Essays on Here- 

 dity," p. 279). 



"The second great factor is natural selection " (345). This requires 

 " indefinite variations," of which there is no proof of such ever existing 

 in Nature. 



The third factor is mutations, but " at present we are totally in the 

 dark as to what causes them " (380). 



The few concluding pages are too hypothetical for any true scientific 

 basis, and the result left on the reader's mind is that authors differ very 

 little from Darwin's original view of his theory expressed by the title of 

 his book, and that they are not sufficiently aware of the value of 

 " response to the direct action of changed conditions of life." 



"Insect Pests of the Farm and Garden." By F. Martin Duncan. 

 8vo., 143 pp. (Sonnenschein, London, 1906.) 2s. Qd. net. 



After a brief outline of the main points in the structure of insects, the 

 author deals with the appearance and occurrence of some of the principal 

 insect pests of farm and garden. Some of the best-known remedies are 

 detailed. 



Most of the illustrations are from photographs. Photographs of 

 insects leave very much to be desired, and are far less useful than well- 

 executed drawings ; and, in any case, the lack of an indication of the actual 

 size of the creatures is a serious omission. 



" Woodside, Burnside, Hillside, and Marsh." By J. W. Tutt, F.E.S. 

 8vo., 241 pp. (Sonnenschein, London, 1906.) 2s. 6d. net. 



A little book dealing in simple and interesting fashion with the 

 common objects, plants, and animals of the country. 



"Butterflies and Moths of the United Kingdom." By W. E. Kirby. 

 8vo., lii -f 468 pp. (Koutledge, London, n.d.) 7s. 6d. net. 



This book will be welcomed by many nature lovers, since it gives a 

 coloured figure and description of every British butterfly and moth, 

 including several of those which once occurred but have long been 

 extinct. Types of the smaller moths (Micro-lepidoptera) are also figured 

 and described. Where known the caterpillars and chrysalides are also 

 described, and in many instances figured, and notes upon the food plants, 

 time of appearance, and so on, add greatly to the value of the book. 



No attempt has been made to bring classification up to date, but no 

 book could be more welcome than this to a young "moth hunter" nor 

 better serve as an introduction to a knowledge of the most popular group 

 of insects. Considering the price of the book the coloured plates with 

 their mostly life-sized figures are admirably done, and two well-made 

 indexes add to its usefulness, 



