3H 



NATURE 



[May 27, 1920 



to the analysis of coal, proximate and ultimate ; 

 these, compared with the preceding- sections, are 

 remarkably full and evidently based upon 

 personal experience. It would have added to the 

 comprehensiveness of the account if a description 

 of the methods of determining arsenic had been 

 gfiven. Owing to leg-islation arising out of the 

 arsenic-in-beer scare the value of coal, especially 

 anthracite, for kilning purposes is greatly affected 

 by the presence of even small quantities of 

 arsenic. The method of determining the calorific 

 value of coal would have been rendered more in- 

 telligible if the description had been accompanied 

 by an illustration of the calorimeter. Lastly, we 

 deprecate the practice of placing the bibliographical 

 references in the text at the end of the book. This 

 method, at least as regards chemical literature, 

 seems to have originated in Germany. We fail 

 to perceive that it has a single redeeming feature. 

 On the contrary, it produces the maximum 

 amount of inconvenience. It involves constant 

 turning backwards and forwards, which is apt 

 to become tiresome and to lead to error. It is 

 far preferable to embody the references in the 

 text, or at least to place them as foot-notes to the 

 pages on which they occur. 



A Standard Book on Soils. 



The Soil: An Introduction to the Scientific Study 

 of the Growth of Crops. By Sir A. D. Hall. 

 Third edition, revised and enlarged. Pp. xv + 

 352. (London : John Murray, 1920.) Price 

 75. 6d. net. 



IT is pleasant to see that Sir Daniel Hall's book 

 on the soil has now reached a third edition. 

 It will have a permanent place in British agricul- 

 tural literature as the first book on the subject in 

 the modern period. Its distinguishing feature, 

 which marked it off from its predecessors, is its 

 clear recognition of the complexity of the soil 

 problem, emphasised in the opening words and 

 maintained throughout : " In the scientific study 

 of soils, chemical, physical, and biological con- 

 siderations are involved." Successive generations 

 of earlier workers had regarded soil fertility as 

 essentially chemical, physical, or bacteriological. 

 This book was the first to show British readers 

 that all these different views had a basis of truth, 

 but that each by itself was too narrow. The study 

 of the soil, in short, cuts across the conventional 

 divisions of science and brings together such 

 apparently diverse workers as the physicist and 

 the protozoologist, the mathematician and the 

 plant physiologist, and others who in an ordinary 

 scientific laboratory would be supposed to have 

 nothing in common. 



NO. 2639, VOL. 105] 



To. write an adequate review of the book, com- 

 paring it with the preceding editions, would be to 

 write a history of the development of modern 

 soil science, and could not be done in a short 

 notice. The leading advances have been in our 

 knowledge of the constitution of the soil and of the- 

 population inhabiting it. In both directions recent 

 investigations have revealed greater complexity 

 and emphasised still further the need for "team " 

 work to supplement the indispensable, but limited, 

 individual work. 



Ten years ago there was only one soil biologist 

 at Rothamsted ; now there are nine, and others, it 

 is hoped, will soon be added. Bacteria were at 

 first supposed to be the only organisms con- 

 cerned; now it is realised that fungi, actino- 

 mycetes, algse, and protozoa are all present in the 

 soil, and probably all concerned in some way in 

 the great changes going on. 



Sir Daniel stimulates a living interest in the 

 subject and makes constant reference to the ex- 

 perience of farmers, gardeners, and others in soil' 

 management and in the behaviour of plants in 

 different soil conditions. These serve to show 

 the student how much remains to be done in spite 

 of all the advances of recent years; in this way 

 also the book acts as a valuable corrective to the 

 tendency showing itself in certain modern text- 

 books of regarding the soil as a physico-chemical 

 system the properties of which are expressible in 

 mathematical terms. These analytical methods 

 have their uses, but they would become dangerous 

 if they were allowed to obscure the complexity of 

 the problem. 



There is a valuable section on soil types con- 

 taining much information of interest to the ecolo- 

 gist as well as to the agriculturist. The section 

 on land reclamation is of particular interest at the 

 present time and has a breadth of view and a free- 

 dom from extravagent anticipations rarely found 

 in discussing this important subject. Altogether 

 the book keeps up its reputation and will prove 

 invaluable to the serious student of the subject. 



E. J. R. 



Savages of the Far Past. 



An Introduction to Anthropology: A General 

 Survey of the Early History of the Human Race. 

 By the Rev. E, O. James. Pp. ix + 259. (Lon- 

 don: Macmillan and Co., Ltd., 1919.) Price 

 7s. 6d. net. 



MR. JAMES aims at introducing the student 

 not so much to anthropology in general as 

 to prehistoric archaeology interpreted in the light 

 of the study of primitive man, modern as well as 

 ancient. After an introductory chapter outlining 



