570 



NATURE 



[October i i, 1900 



two maps representing the " Florareiche " and the 

 "Faunareiche" respectively. Much might be said with 

 respect to the divisions adopted by the author, but space 

 forbids. 



The book is abundantly illustrated, and most of the 

 illustrations are well selected and quite to the point ; but 

 exception might perhaps be taken to some of the pictures 

 in which the author attempts to represent as many types 

 as possible in one plate, with the usual consequence that 

 the ensemble looks unnatural and untrue. The map 

 showing the distribution of the European species of 

 Asplenium (p. 89) is not very illustrative and scarcely in 

 place ; whilst Kerner's maps dealing with Tubocytisus 

 (pp. 90, 91) require thorough revision, although they are 

 excellent so far as method is concerned. 



Otto Staff. 



FOUNDATIONS OF AGRICULTURE. 

 Agricultural Botany — Theoretical and Practical. By 

 John Percival, M.A.(Cantab.), F.L.S. Pp. xii + 798. 

 (London : Duckworth and Co., 1900.) 



THE professor of botany at the South-Eastern Agri- 

 cultural College at Wye has done well to depart 

 from the utterly inefificient standard of text-books in 

 this subject hitherto set and followed in this country ; 

 and, although we do not think the best possible has yet 

 been produced, the present work is so distinctly an im- 

 provement, and so clearly sounds the right note, that we 

 have no hesitation in recommending it as the elementary 

 handbook for the agricultural student. What it lacks most 

 conspicuously is a clear enunciation of the principle 

 underlying the teaching of botany to students of agricul- 

 ture, and it will be just as necessary for the teacher using 

 this book, as it is for him who uses others, to emphasise 

 the point of view (lost sight of in nearly all our text, 

 .books) that the plant is a focussing centre in which are 

 concentrated the materials gathered by roots and leaves 

 and the solar energy fixed by the chlorophyll-action, so 

 that plant substance — be it in a cabbage, a potato, 

 a crop of wheat or an oak forest — represents a real gain 

 of energy from the surrounding universe, stored up with 

 an equally real recovery of material which would other- 

 wise have been lost to us because dissipated into the 

 atmosphere in an unavailable form. It is this which 

 makes farming, planting, forestry and other branches of 

 agriculture so fundamentally different from the mining 

 industries, where the coal, iron, &c., brought from 

 their storehouse in mother earth are merely temporary 

 sources of wealth representing expenditure of capital. 



As regards features of technical detail, there are several 

 interesting departures from the repetitions of previous 

 text-books, and our chief regret is that these are not more 

 original in conception and treatment. For instance, the 

 section on recognition of trees and shrubs by means of 

 twigs in winter is a very welcome one, but it might 

 have been made far better. Again, the part dealing 

 with our common grasses could have been improved 

 by bolder departures from, and less reliance on, Con- 

 tinental and other authorities in common use, though 

 it should be pointed out that the author has, at any 

 rate, provided new drawings of the " seeds " of most of 

 NO. 161 5, VOL. 62] 



the grasses. This, however, not always with advantage 

 — e.g. the very bad figure (210) of Yorkshire fog. Nor do 

 we regard the summary of characters leading to the 

 recognition of grasses by their leaves as either adequate 

 or worthy of the scope of the book ; it might have been 

 made much better with a little attention to points not 

 included in ordinary pamphlets on the subject. 



These are faults to be remedied in later editions, and 

 must not be allowed to outweigh the really excellent 

 portions of the book dealing with the various large groups 

 of cultivated farm-plants — e.g. Chapter xxv., dealing with 

 the hop, is well done, as are Chapters xxxiv.-xxxviii., deal- 

 ing with those very difficult subjects, the varieties of our 

 cereals. Indeed, we may commend the whole of this 

 part of the work which treats of the classification and 

 special botany of farm crops, with few reservations, such as 

 those hinted at above, as an admirable summary of what 

 the student should direct his attention to in this depart- 

 ment of his studies. The general botany is also fairly 

 well done ; and although we do not consider the section 

 on " Internal Morphology " quite happy either as regards 

 selection of subjects or treatment of details, we have 

 little but praise for the part dealing with physiology, 

 which is so markedly in advance of the stuff we are too 

 apt to meet with in existing agricultural text-books in this 

 country, that we prefer to dwell only on its merits. The 

 chapters on weeds and on diseases of farm-plants are also 

 distinctly better than those in any previous English works 

 dealing with agricultural botany, and we heartily con- 

 gratulate the author on his exhibition of capacity in the 

 role of a teacher of elementary students of agriculture. 

 At the same time, we would point out that much may be 

 done in future editions to improve this subject, and still 

 more in improving and extending the account of the 

 doings of bacteria in the soil. The agricultural 

 student ought to be made to realise that the 

 soil is a matrix, in which the rocks and salts, 

 water and other lifeless constituents, play little 

 more than the subordinate parts of a skeleton or 

 scaffolding, on and between which the real work of 

 conversions, transferences, destructions and constructions 

 of materials necessary for the life of higher plants are 

 being carried out by lower organisms of many different 

 kinds. A vivid picture of the struggles of root-hairs for 

 salts and' oxygen, of the relations between anaerobic 

 and aerobic organisms, of the dangers of attack from 

 parasites here, and of the missing of advantageous con- 

 nections with symbiotic helpmeets there, and of the 

 mutual interactions of the living and non-living factors 

 in keeping up the " fertility," moisture, heat, &c., of the 

 complex soil, would be a fitting subject for a chapter 

 designed to knit together the enormous number of facts 

 here thrown down before the unwary student, and among 

 which he is sure to stumble and flounder. 



The ideal here sketched is not an easy one to attain, 

 and we are aware that facts are coming in every day, and 

 that our knowledge of the factors concerned is still in 

 its infancy. Nevertheless, it is no empty compliment 

 to the author to point out that there are indications 

 in the present book that he would be quite capable of 

 putting the crown to his really excellent attempt at 

 an elementary text-book for agricultural students, 



