June i, 191 iJ 



NATURE 



443 



THE FEEDING OF CROPS AND STOCK. 

 The Feeding of Crops and Stock. An Introduction 

 to the Science of the Nutrition of Plants and 

 Animals. By A. D, Hall, F.R.S. Pp. xvi + 298. 

 (London : John Murray, 191 1.) Price 55. net. 



THIS volume is the third of a series by Mr. Hall 

 dealing with some of the scientific aspects of 

 farming, and, like the preceding treatises, on "The 

 Soil" and "Manures and Fertilisers," gives an ex- 

 ceedingly clear and able exposition of the principles 

 of crop and stock feeding, valuable alike to student, 

 teacher, and practical farmer. It might be well if 

 Mr, Hall would at a convenient time consider the 

 rearrangement of the series, as at present there is 

 some overlapping of subjects which is particularly 

 noticeable in the present volume. 



The first four chapters are devoted to the study 

 of the growth of and the chemical changes occurring 

 during the growth of plants. The important points 

 in this process are illustrated by simple experiments 

 which can be performed without the aid of com- 

 plicated apparatus, and which we particularly com- 

 mend to teachers of " nature-study " in our elemen- 

 tary and secondary schools. Chapters v. to viii. deal 

 with matter which is more fully elaborated in Mr. 

 Hall's work on "The Soil." Chapters ix. to xi. 

 break fresh ground in dealing with the animal and 

 its food requirements, whilst chapters xii. and xiii. 

 are digests of Mr. Hall's treatise on " Fertilisers and 

 Manures," the last chapter^ xiv., containing a short 

 account of the composition of milk and other dairy 

 products. 



The subject of the feeding of animals is one to which 

 we could wish the author had devoted more space. 

 Rothamsted has a wealth of results of its researches 

 on the feeding of plants, but the subject of animal 

 feeding has not received the same attention, though 

 by this it must not be understood that extremely 

 valuable work in that direction has not been accom- 

 plished, but it is a sad fact, appreciated by all workers 

 in agricultural science, that in England we have no 

 well-equipped station for the carrying on of necessary 

 research in animal nutrition. The United States and 

 Continental nations have seen the importance of such 

 work, and the experimental work of these countries 

 is rich in results, of which Mr. Hall has made excel- 

 lent use, and we feel confident that had Rothamsted 

 the equipment for such work which its reputation 

 and the personnel of its present staff deserve, our 

 knowledg^e of the feeding of animals would be greatly 

 increased, to the benefit of the stock feeders of the 

 country. Will not some friend of agriculture come 

 forward and establish at Rothamsted a digestion 

 calorimeter and endow its efficient service? 



Mr. Hall has, in the work under review, disposed 

 of many fallacies with regard to plant and animal 

 nutrition, and we would commend to all practical 

 men the pages dealing with the valuation of foods 

 and the use of the various constituents of foods in 

 the stacres of fattening. (An omission in proof cor- 

 rection of the first few lines of p. 181 in speaking 

 of the cottoncakes may give rise to some misunder- 

 standing.) To the stock farmer it will lie oli\i(i!m 

 NO. 2170, VOL. 86] 



that there is much in the book to interest, and if not 

 to instruct him, at least to explain the principles on 

 which his good practice depends, and to the arable 

 farmer there is also much which, from the purely 

 practical point of view, may show the way to 

 economics in manuring by a well-reasoned explana- 

 tion of the influence of manurial constituents on 

 plants havinp- differing range of root action, differ- 

 ing periods and durations of growth, and differing 

 final products to build up. Such an important point 

 as the quality of wheat is elaborated, with a due 

 consideration of all the factors, and one-time accepted 

 theory that the order of the evaluation of the protein 

 and starch is the cause of the wide variations in 

 qualitv between strong Canadian and weak English 

 wheats is regarded as untenable. 



As has been already stated, many formerly accepted 

 theories are rejected, and sound reasons brought for- 

 ward for their rejection, the reasons for crop rota- 

 tions, the acid excretion by roots, the changes in- 

 duced bv ensiling, the use of preservatives for farm- 

 yard manure, effect of food on milk, are among 

 many changes of opinion which have been brought 

 about bv accurate researches into cause and effect, and 

 although the practical man is apt to be bewildered 

 by these changes of opinion and to be somewhat 

 sceptical as to the accuracy of present theories, the 

 fault lies with those who have in the past hastily 

 enunciated reasons without due consideration of all 

 the factors, not to those who, like the author of this 

 book, demand that a theory shall be not merely a 

 plausible explanation of phenomena, but something 

 which will rigorously satisfy all requirements, and the 

 truth of which can be demonstrated by an appeal to 

 accurate experiment. M- J- R- D. 



PATHOGENIC INSECTS. 

 Insects and Disease: a Popular Account of the Way 

 in ivhich Insects may Spread or Cause some of 

 our Common Diseases. By Prof. R. W. Doane. 

 Pp. xiv + 227. (New York: H. Holt and Co.; 

 London: Constable and Co., Ltd., 1910.) Price 

 TTso dollars net. 



IN this volume, which gives evidence of cxinsider- 

 able research, Prof. Doane li.is pi< -rnicd the 

 first collective narrative, in popular form, of the 

 principal results which have been achieved in relation 

 to insect-borne diseases, both in man and his domes- 

 ticated animals. And in order that the layman may 

 the more readily understand the biological relations 

 of the various pathogenic organisms and their inter- 

 mediary hosts, the author has briefly reviewed some 

 of the more salient points in relation to their structure 

 and life-history; in this way it is believed that the 

 most complex inter-relations may be followed clearly. 

 Prof. Doane has met a great want in pnxlucing 

 this unpretentious volume, in which he has success- 

 fully collated the overwhelmintr evidence of the male- 

 ficent agency of certain inso^ n 1 <Mhcr allied 

 animals in the dissemination <.l <'•' We feel, 



however, that he has been a liiii dulous in 



sdine few instances in acceptina .\;.i n. wliich is 



