June 17, 1922] 



NA TURE 



769 



i 



been economically transformed into products such as 

 stainless steel, stainless iron, and transformer iron. 

 The use of the last named has increased the efficiency 



1 electric transformers to an extent which represents 



n annual saving of hundreds of thousands of tons of 



oal per annum. 

 At one time the induction furnace received con- 

 siderably greater prominence than the arc furnace. As 

 the author states, many furnace designers, beheving 

 that the principle of induction heating was superior, 

 concentrated their efforts on the production of a furnace 

 which could operate on any standard electric supply 

 md at the same time meet all the requirements of the 



: eel-maker. The position to-day, however, is that 

 almost the entire output of electric steel is made from 

 arc furnaces. The book is clearly printed and well 

 illustrated and will certainly repay study by all those 

 interested in the subject. 



Physiology of the Growing Plant. 



Encydopedie scientiiiqtie : BibUotheque de Physiologie 

 et de Pathologic vegetales : Nutrition de la plante. 

 Par M. Molliard. I. Echanges d'eau et des sub- 

 stances minerales. Pp. xiv-l-395. II. Formation 

 des substances terraires. Pp. vi + 438. (Paris: 

 Gaston Doin, 1921.) 14 francs each vol. 



A SERIES dealing with the physiology of the grow- 

 ing plant in health and disease is being written 

 by Prof. Molliard, Dean of the Faculty of Science of the 

 University of Paris, and the two volumes under notice 

 are the first to be issued. The scope of the series is 

 wider than would usually be undertaken by a single 

 writer, but the author considers that the advantages 

 of uniform treatment will outweigh the disadvantages 

 arising from the attempt to cover so extensive a field 

 of science. 



The volumes before us deal with the nutrition of 

 tlie plant, the phenomena of absorption of nutrients 

 from the soil, the building up of complex substances 

 in the plant and their translocation from leaves to 

 storage organs. The author has succeeded in bringing 

 t^ogether a great amount of material that cannot 



Lially be found in the same book, and this will prove 

 ci convenience to students. As an example, under 

 the heading " Glucosides " there is not only the usual 

 chemical account of these substances, but illustrations 

 of cross-sections showing the distribution of typical 

 glucosides in growing plants. In this and in other 

 directions, the volumes give to the chemist much 

 information that he does not possess although it may 

 be well known to the botanist, and they give to the 

 botanist a survey of chemical relationships which he 

 might not find so easily elsewhere. 

 NO. 2746, VOL. 109] 



It could scarcely be expected that a book covering 

 so much ground could include anything like all the 

 recent work. The section on soils, for example, 

 contains no reference to many of the investigations 

 made during the last few years. The only grouping 

 of fractions in mechanical analysis of which mention 

 is made is that of Wollny, drawn up forty years ago, 

 no reference being made to the important later develop- 

 ments made in the United States, Great Britain, 

 Sweden, or elsewhere. Similarly also, it is assumed 

 that soil possesses the sand-grain structure formerly 

 attributed to it, although this view is now displaced 

 by the later colloidal hypothesis. Fuller justice is 

 done, however, to recent French work, and it is in 

 the. summaries of some of these interesting and 

 suggestive investigations that English readers will 

 find the chief interest of the book. 



We should like to suggest that in future volumes 

 there should be more references showing the sources 

 from which the tables are taken. A considerable 

 nurtiber of figures are given, but it is not easy to know 

 the exact conditions under which they were obtained, 

 and, as every one who has studied plant nutrition is 

 aware, the phenomena are profoundly affected by 

 alterations in the conditions under which the plant 

 is growing. In particular the section dealing with the 

 mineral constituents of plants would have been greatly 

 improved by fuller references. 



Life among the Sema Nagas. 



The Sema Nagas. By J. H. Hutton. Published by 

 the direction of the Assam Government. Pp. xviii -f- 

 463. (London : Macmillan and Co., Ltd., 192 1.) 

 405. net. 



R. HUTTON has quickly added to his mono- 

 graph on the Angami Nagas a second de- 

 scribing the allied tribe, the Sema. The latter occupy 

 the watershed dividing Assam from Burma, the plateau 

 and the valleys of three rivers, the most important, the 

 Dayang, eventually flowing into the Brahmaputra and 

 so into the Ganges, the other two mingling their waters 

 with the Lania, and reaching the sea by way of the 

 Ti-Ho, the Chindwin, and the Irawadi. The Sema 

 Nagas are a mixed race, the result of emigration from 

 at least three directions : from the north-west, whence 

 came the Singpos, Kacharis, and Garos ; from the 

 south the Angamis; while a migration from south 

 northwards on the part of the Thado Kukis and 

 Lusheis has scarcely ceased even now. 



Mr. Button's work is the result of eight years' 

 acquaintance with the Sema Nagas, during which he 

 learned to speak their language, which had not hitherto 

 been reduced to writing, and gained the confidence of a 



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