BOOK REVIEWS. 



87 



ridiculous. As gardeners and their employers frequently lay out their 

 own gardens, this book will be very helpful, and also the young man 

 adopting landscape gardening as a profession will find much service- 

 able matter. Good printing and an excellent index help to make the 

 book one that garden-makers should possess. 



"Fungous Diseases of Plants." By B. M. Duggar. 8vo. 

 xii4-508 pp. (Ginn, London, 1909.) 8s. 6d. 



Though written especially for American growers, this book will be 

 found most useful for England too, for unfortunately the diseases of 

 plants in one district are apt to spread all too rapidly to others, ,and 

 American plant diseases have made their unwelcome appearance here 

 in many cases, while European parasitic fungi have not been slow to 

 make their way to America. Further, the remedies and methods of 

 prevention are necessarily very similar on both sides of the Atlantic. 



The book is not only useful for the cultivator, but for the student 

 of pl^nt diseases as well. It is accurate, comprehensive, well printed, 

 and well illustrated, and contains descriptions of methods of work, 

 and references to some of the important literature of plant disease 

 under each separate heading. We have used the book with profit, 

 and can confidently recommend it to others. 



" Plant Life and Evolution." By D. H. Campbell. 8vo. 360 pp. 

 (Holt, New York, 1911.) $1-60 net. 



This book contains ten chapters as follows: "Introduction," 

 " Factors in Evolution," " Lower Plants," " Origin of Land Plants," 

 "Seed Plants," " Angiosperms, " "Environment and Adaptation," 

 "Problems of Plant Distribution," "Human Factor in Plant Dis- 

 tribution," and "The Origin of Species." 



In the Introduction the author observes that ' * We have no positive 

 evidence . . . that ' vital ' phenomena are not reducible to terms 

 of physics and chemistry," and that " living matter is not subject to 

 the same laws that govern inorganic bodies." To a large extent this is 

 true: thus respiration is combustion, the waste products of carbonic 

 acid and water being the same; but the obvious "purpose" every- 

 where to be seen in organic beings, could not possibly bo the result 

 of "blind forces" and "inert matter." Life is their director 

 throughout. 



Speaking of Do Vries' mutations as the origin of species, such 

 may be true provided the new characters produced are sufficient and 

 distinct enough for systematic botanists to regard them as specific. 

 Prom a study of De Vries' books, as a rule, they do not appear to be 

 so, being simply the results of a sudden change from a " nearly pure 

 sandy soil" to a "richly manured" one, as he tells us, and the 

 difference lies mainly in foliage. It is the " change in the conditions 

 of hfe,'' as Darwin calls it, which excites the variability of the plant, 

 and it is only a question of degree whether the result of the plant's 

 response is enough to make a species or not. 



