332 



NATURE 



[January 21, 1909 



reading perfection is not aimed at ; in one case (p. 68) 

 several errors occur in a few lines. 



The chapter on adjustment to light deals with 

 light stimuli, the measurement of light, and the pro- 

 cess of photosynthesis. Under " .Adjustment to Tem- 

 perature " the relation of plants to temperature is 

 included along with digestion, respiration, germin- 

 ation, nutrition of hysterophytes, growth, reproduc- 

 tion, and propagation. The connection of all these 

 with temperature is not very obvious, as they are the 

 •outcome of many factors. In an ecological text-book 

 -one might well expect a more recent treatment of 

 ^•propagation, a subject of prime importance, and one 

 to which Danish and Swiss workers have given much 

 attention. The chapters on adaptation to water and 

 to light include all structural changes, and they pro- 

 ceed on conventional lines: decrease of water-loss 

 through leaf position, rolling of the leaf, changes 

 of epidermal cells, stomata, &c. ; types produced by 

 adaptation to water, xeiophytes, &c. ; the relation of 

 organs to light, types of leaves as determined by light, 

 and other topics. " The Origin of New Forms " 

 (chapter ix.) includes a short history of evolution, and 

 sketches rapidly origin by adaptation, variation, and 

 other processes. 



The latter part of the book (chapters x.-xv.) shows 

 Prof. Clements at his best. His views as given in 

 "Research Methods" have already had great in- 

 fluence; these form the basis of the chapters in the 

 present work, but the new arrangement is a great im- 

 provement on the old. The study of vegetation by 

 quadrats and transects is now a recognised method of 

 the ecologist, and the chapter on it forms a good intro- 

 duction for the advanced student. The plant forma- 

 tion (chapter xi.) is defined as " an area of vegetation, 

 such as a meadow, a forest, a prairie, a bog, a clifT 

 •covered with lichens, or a pond of water-lilies." The 

 cautions given under " recognition of formations " 

 are timely, because " the unit itself shows parts which 

 may be mistaken for formations "—a very common 

 error. The formation depends on habitat, and is a 

 product of it, but the author wisely points out the 

 existence of a historical factor " due to the accidents 

 of migration and competition, or to the fact that the 

 |ilant itself has a certain ancestral or historical 

 quality that enables it to persist." No student of 

 ecology can omit to read carefully the description of 

 the formation, or ■vvhat one naturally calls the 

 "Clements formation"; it matters little whether it 

 is synonymous with the conceptions of other authors, 

 but it is an introduction to the varying phases of vege- 

 tation which in its definiteness and detail has few 

 rivals. The chapters discussing aggregation and 

 migration (xii.), competition and ecesis, or the adjust- 

 ment of a plant to a new habitat (xiii.), invasion and 

 succession (xiv.), and alternation and zonation (xv.) 

 are all important; they deal with features one con- 

 stantly meets in the field, and these chapters will 

 assist much in giving that mental perspective so 

 greatly needed in Britain, where the units of vegeta- 

 tion arc limited in extent and liable to disturbance. 

 The irritating nomenclature of " Research 

 NO. 2047, \-OL. 79] 



Methods" does not appear in this book; such terms 

 as are retained are few, and so useful that they have 

 already been adopted. The illustrations, where they 

 refer to ecology, are helpful and are well reproduced. 

 The provision of an index is an improvement on the 

 author's former book, but we think the omission of 

 references to literature is not justifiable in this period 

 of ecology and in a book which is obviously only feel- 

 ing its way. The publication of this book will have a 

 marked influence on teaching, and it is well that one 

 backed by so much experience should lead the way. 

 The enthusiasm of the author can be traced through 

 every page ; ecology is always in his mind, and he 

 weaves it into botanical teaching from the commence- 

 ment. The course leads in the right direction, al- 

 though slight differences of opinion on detail may be 

 inevitable. W. G. S. 



MARINE METABOLISM. 

 Conditions of Life in the Sea. A Short Account of 

 Quantitative Marine Biological Research. By J. 

 Johnstone. Pp. xiv + 332. (Cambridge : University 

 Press, 1908.) Price 9^. net. 



SINCE Hensen published, in 1887, the first account 

 of his methods for the quantitative estimation 

 of the plankton, an ever-increasing number of workers 

 has entered the field of marine biological research. 

 To quote from the author in the preface : — " It is 

 characteristic of a really great idea in science that it 

 should stimulate further discovery by the suggestion 

 of new lines of research and new methods of investiga- 

 tion." .Already many results of the greatest interest 

 have been obtained, and the lines on which modern 

 research is being carried out are rich in promise. The 

 absence of any adequate summary of these researches 

 has been a serious gap in scientific literature, for on 

 account of the diversity and inaccessibility of a great 

 number of the memoirs, this subject still remains a 

 terra incognita to the great majority of readers. To 

 meet this demand in .a satisfactory manner the range 

 of the subjects that would have to be entered into is 

 very considerable; and Mr. Johnstone is to be con- 

 gratulated on the masterful manner in which he has 

 carried out this task in writing " Conditions of Life 

 in the Sea." .\ clear and concise account of all the 

 more important work is given in language devoid of 

 unnecessary technicalities, and in dealing with the 

 more speculative problems the author states pro and 

 con. with an impartiality which is quite refreshing. 



Part i. is an introduction to the problems discussed 

 later on in the work, and is primarily intended for 

 the benefit of those who have no special knowledge of 

 oceanography. .\ short account is given of the gear 

 and methods of the marine biologist. Facts relating 

 to the geology and to the hydrographical and physical 

 conditions of the north-western ocean are summarised. 

 The reader is made familiar with the commoner and 

 more widely distributed marine fauna and flora, special 

 reference being made to the plankton. Finally, the 

 economic and biological importance of the fishing 

 industries is briefly outlined. 



I 



