698 



SCIENCE. 



[N. S. Vol. XXI. No. 540. 



more generous use of italics. Mr. Ruther- 

 iord is apt to express himself with no uncer- 

 tain sound against the interminable drawl of 

 less gifted investigators. Nevertheless, the 

 subject of radioactivity, which is now in the 

 glare of the footlights, may not be there in- 

 definitely, and a more liberal variegation of 

 the text for the benefit of the lazy reader, may 

 not in any case be an unreasonable conde- 

 scension. 



To have produced a fresh book, broad in 

 scope and accurate in its statements, on a 

 subject which has now for years been the chief 

 topic of animated discussion in the physical 

 and other magazines, is Mr. Rutherford's great 

 merit in this work, quite apart from its char- 

 acter as a summary of original investigation. 



Carl Barus. 



Bkown Un'iveksity, 

 Pkovidekce, R. I. 



Die Ernahrung der landivirtschaftlichen 



Nutztiere. Von Dr. O. Kellner, Geh. 



Hofrat imd Professor, Vorstand der Kgl. 



landw. Versuchstation Mockern. Berlin, 



Paul Parey. 1905. 8vo. Pp. viii + 594. 



Cloth. Price 13 Marks. 



Notwithstanding the vast amount of in- 

 vestigation upon stock-feeding problems which 

 has been carried on during the last forty years 

 in the experiment stations of Germany and 

 later of the United States, as well as to a 

 certain extent elsewhere, it is unfortunately 

 true that the theoretical basis of the subject 

 has shown relatively little advancement since 

 Henneberg's earlier researches in the sixties. 

 We still, as then, reckon largely with the so- 

 called ' digestible nutrients ' (protein, carbo- 

 hydrates and fat) and still assume that their 

 amount measures, at least approximately, the 

 nutritive value of feeding stuffs. True, we 

 have had an uneasy consciousness for some 

 time that this was far from being strictly cor- 

 rect, but in the absence of any better method 

 of comparison we have rather blinked the fact 

 and each writer has followed in the footsteps 

 of his predecessor with, perhaps, the addition, 

 of late years, of some more or less critical 

 statements regarding energy values. 



Dr. Kellner's book marks a new departure 



in the literature of the subject. Its well- 

 known author was the first to suggest, in the 

 year 1880, in connection with investigations 

 upon the nutrition of working horses, that the 

 values of different feeding stuffs might be 

 compared upon the basis of their content of 

 potential energy. Within a comparatively few 

 years thereafter the study of the food as a 

 source of energy to the animal organism was 

 systematically taken up by Eubner and the 

 foundations of the subject were laid. Since 

 then a large amount of investigation upon the 

 nutrition of carnivorous animals and of man 

 has been executed in which Kubner's work has 

 furnished the guiding idea. As regards the 

 nutrition of domestic herbivorous animals, 

 however, scarcely any investigations had been 

 made from this standpoint when, in 1893, Dr. 

 Kellner was called to the directorship of the 

 Mockern Experiment Station. There he at 

 once took up the subject, his first results and 

 an outline of his methods being published in 

 1896. Since that time the work has been 

 carried forward vigorously under his direction 

 and most important results have been se- 

 cured. 



The present book embodies the results of 

 Kellner's investigations, including many that 

 have as yet been published only in abstract, 

 but covers a much broader field than a mere 

 compendium of this work and is an attempt 

 to treat the subject of stock feeding systemat- 

 ically from the new standpoint. The book is 

 divided into three parts. Part I. treats of the 

 composition, digestibility and utilization of 

 feeding stuffs, containing chapters upon the 

 constituents of feeding stuffs, the digestibility 

 of the feed, the iitilization of the digested ma- 

 terials in the animal body, the metabolism of 

 matter and energy under various conditions 

 and the influence of muscular work on metab- 

 olism. Part II. treats of feeding stuffs, cov- 

 ering such subjects as methods of harvesting 

 and preserving, the preparation of feeding 

 stuffs and a somewhat detailed description of 

 the different feeds. Part III. treats of the 

 feeding of farm animals imder the conditions 

 of agricultural practise, including mainten- 

 ance feeding, the fattening of mature animals, 

 the feeding of working animals, the feeding of 



