INDUSTRIAL PROGRESS DURING THE YEAR 1875. ccxxiii 



tions in showing that lack of nitrogen diminishes not only 

 the whole crop, but also its percentage of nitrogen, and that 

 the straw in this case suffers more than the seed. We have 

 space for only the briefest reference to the interesting studies 

 of Lehmann on the compounds of nitrogen best adapted to 

 the nutrition of plants ; by Schloessing on the absorption of 

 ammonia by plants ; by Bretschneider and others on the nu- 

 trition of sugar-beets ; by Mayer and Wolkoff on the res- 

 piration of plants ; and by Fittbogen on the evaporation of 

 water from the oat plant. 



The subject of the nutrition of domestic animals, or, to 

 speak more generally, that of animal physiology, has been 

 actively studied during the past year by feeding experi- 

 ments in the experiment stations and elsewhere. 



Among the more important investigations published are 

 those of Wolff, Stohmann, Ktihn, Marcker, Schulze, Fleischer, 

 Hoffmeister, Heiden, Voit, Weiske, Wildt, and Pott. 



Among the subjects investigated have been the digestion 

 of different foods by different animals ; the effect of fodder 

 on milk production, the functions of the ingredients of foods, 

 as the albuminoids, carbohydrates, and fats, in the formation 

 of flesh and fat, and in the production of animal heat and 

 muscular force. 



The results of the year's work are not characterized so 

 much by the discovery of new principles as by the confirma- 

 tion and elucidation of those previously propounded. 



For instance, one of the important principles brought out 

 by the late German researches is that the carbo-hydrates, as 

 starch and sugar, or easily digestible foods rich in these, as 

 potatoes, when fed in considerable quantities with coarse 

 foods, as hay and straw, decrease the digestion of the latter, 

 while albuminoids or concentrated foods rich in these have 

 no such effect. This is very strikingly exemplified in feed- 

 ing experiments by Wolff, Marcker, Schulze, and Stohmann. 

 So, likewise, the principle that a part of the woody fibre of 

 plants, to wit, the cellulose, is digestible by ruminants and 

 even horses is confirmed by several experiments of the same 

 chemists. 



The question from what ingredients of the food the fat in 

 the body is made up is still hotly discussed, one main point 

 in the controversy being whether the fat formed in the body, 



