November 21, 1901] 



NA TURE 



present case, lustra-cellulose is not silk at all. Why, 

 therefore, call it silk ? Messrs. Cross and Bevan likewise 

 correct the oft-repeated statement that lustra-cellulose is 

 highly inflammable, and point out that "Lehner" silk, 

 which has been denitrated, contains only o'lg per cent, of 

 nitrogen. 



There are many other sections in the book which we 

 should like to dwell upon, but space forbids. We would 

 only draw attention to the articles on constitution, fur- 

 furoids and industrial developments, all of which are of 

 great interest. 



The book before us is to a certain extent disjointed, 

 but we have already stated that it consists largely of 

 abstracts, therefore it is hardly to be expected that the 

 authors could construct a connected narrative. In their 

 anxiety not \.o pad, the authors have, at times, niade the 

 text almost too bare. For this reason it is sometimes 

 hardly as clear as one could wish. This, however, is only 

 a minor blemish. Messrs. Cross and Bevan are experts in 

 this branch of chemistry, and have presented us with a 

 book which is replete with important matter. It is not a 

 book for the tyro, but we sincerely trust that it will be 

 widely read by chemists, and we believe that research 

 work on cellulose will be thereby greatly stimulated. 



F. MOLLWO Perkin. 



OUR BOOK SHELF. 



Pp. 



Irish Topographical Botany. By R. L. Praeger, 

 clxxxviii -t- 410. (Dublin : Hodges, 1901.) 



Practiial Text-book of Plant Physiolooy. By D. T. 

 Macdougal, Ph.D. Pp. xiv -f- 352. (New York and 

 London : Longmans, Green and Co., 1901.) Price ~s. bd. 

 net. 



The botanical survey of a country demands a good deal 

 from the men who undertake it, and one source of confu- 

 sion now apparent in the many and various attempts being 

 made in many and various parts of theworld isthe different 

 ideals set up by different workers as to what constitutes 

 a botanical survey. The purpose of Mr. Praeger's well- 

 printed but somewhat heavy book is to give records of 

 the county distribution of plants in Ireland, and the task 

 — probably a thankless one in proportion to the labour it 

 must have cost — seems well done. To our thinking, how- 

 ever, the book is only rescued from being a very dry and 

 bulky reference list by the attempt, in -Section ii. of the 

 introduction, to sketch in outline the botanical features of 

 Ireland in terms of plant communities. 



It must be added, however, that the list appears to be 

 very complete and is accompanied by six excellent maps, 

 and there can be no doubt that the work will be indis- 

 pensable to the reference library of the systematic 

 botanist. 



Dr. Macdougal has written an interesting and, in many 

 ways, an excellent text-book. We have often wondered 

 why plant physiology should so often be treated from the 

 point of view which emphasises the obscure relations 

 between structure and function involved in the phenomena 

 of life and which almost ignores the many side-issues 

 bearing on the practice of plant-culture, and it is a 

 pleasure to see a work in which these latter are kept in 

 view. 



Many of the experiments are neat and well chosen, 

 and the most striking are often the simplest— cj,"". that of 

 Molisch for demonstrating the hydrotropism of roots (Fig. 

 28), or that selected for showing the swelling of seeds on 

 imbibition (Fig. 84). 



Many readers would probably have wished for fuller 

 NO. 1673, VOL. 65] 



discussion of theoretical points. The short state- 

 ment on p. 215, for' instance, as to the ascent of water 

 in plants, is meagre if not misleading. The sentence 

 on p. 8 hardly does justice to Czapek and Pfeffer's 

 clever work on the geotropir region of the root-tip, or 

 to Darwin's beautiful proof that the tips of Setaria 

 seedlings are alone sensitive to the heliotropic stimulus, 

 while the wholesale acceptance of Nemec's conducting 

 fibrillje probably needs further justification. 



.As sometimes happens with .American books, the 

 English reader may be startled, if not puzzled, by some 

 of the expressions — e.g. " the substances illy affected " 

 (p. 57) and " .\ second experiment, exploited by Pfeffer and 

 extended by Czapek" (p. 78) seem to need explanation. 



In spite of faults, however, the book may be welcomed 

 as a useful one. 



Botany, an Elementary Text for Schools. By C. H. 

 Bailey. Pp. xiv-f355. (New York: The Macmillan 

 Company. London : Macmillan and Co., Ltd., 1900.) 

 Price 6j. 



This volume, like all Prof. Bailey's works, bears the 

 stamp of originality, and in many respects forms an 

 excellent model of what a school book on botany ought 

 to be. Naturally the examples chosen for study are 

 such as can be easily pr'ocured in America, but teachers 

 at home might readily learn much from the author. 



The details of plant-structures are introduced in a way 

 calculated to excite the interest and attention of the 

 learner, and the very numerous illustrations are directed 

 to the same end. They are excellently chosen and 

 admirably executed. The portion of the book which is 

 devoted to an account of the minute structure of the 

 tissues strikes us as the weakest part of the whole, and 

 also as perhaps the least useful, having regard to the 

 needs of beginners in the study of plants. The con- 

 cluding pages give directions for forming collections of 

 plants and for determining the species which are likely 

 to be commonly met with. 



Not the least valuable of the lessons to be drawn from 

 Prof. Bailey's book are to be found in the preface, in 

 which much sound advice is given as to the kind of work 

 most suited to the needs of school children. After all, it 

 is the ti'aining which is the thing of real value — the 

 development of the faculties of observation and of 

 drawing right inferences from observed facts. 



(i) Curso Elemental de Fisica Moderna ; {2) Eleinentos 

 de Fisica Moderna. By Dr. R. Pedro Marcolain San 

 Juan. I'l) Pp. 804, with S94 woodcuts ; (2) pp. 492, 

 with 608 woodcuts. (Zaragoza : Emilio Casaiial, 

 igoo. ) 



These are two treatises on descriptive physics, of which 

 the second book is merely an abridged edition of the 

 first. Each is divided into three parts. The first deals 

 with mechanics, including hydromechanics and acoustics ; 

 the second with radiology, including heat as well 

 as light ; and the third with electricity, being sub- 

 divided under the headings of electrostatics, electro- 

 dynamics and electrotechnics. In speaking of the subject- 

 matter as descriptive physics, in contradistinction to 

 mathematical or experimental physics, we mean to imply 

 that the books belong to the class of popular treatises 

 containing a general description of the properties of 

 matter suitable for ordinary readers, and illustrated by 

 pictures of steam engines, barometers, siphons, Atwood's 

 machines, pumps, batteries, water boiled by cold, electric 

 telegraphs and all that sort of thing. It is rather 

 amusing to find in the chapter on general dynamics in 

 the larger volume, not only an account of the mechanism 

 of the Funicular Railway up X'esuvius, but also a 

 description of the crater and of the panorama from the 

 summit. 



