250 



Geueiihe.lm; Prof. H. Miiller, director. — This station has made chemi- 

 cal studies oil the coiupositiou of fruit wines, on the sugars in sweet 

 fruits, on the sulpliuric, sulphurous, and carbonic acids in wine, and 

 on other matters relating to wine manufacture. 



Gottingen; {1) Agricultural Experiment Station] Prof. W. Heiineberg,* 

 director. — The work of the year 1890 was in part a study of the con- 

 stituents of feeding stuffs and in part studies, with the aid of the 

 respiration apparatus, of the processes of the formation of fat and lean 

 meat. The first experiment was with regard to the much discussed 

 ]n'oblem of the artificial digestion of protein, and was designed to settle 

 the question as to the accuracy of the coefficients of digestibility of the 

 protein in feeding stuffs, as determined by experiments in artificial 

 digestion. The indications from these experiments were that the arti- 

 ficial digestion of protein is identical with the natural digestion, but 

 since animals excrete considerable amounts of nitrogen-containing 

 metabolic products, the natural digestion seems to give lower coefficients 

 of digestibility than the artificial. If, then, a method can be devised 

 for estimating the amount of these metabolic products the results of 

 artificial digestion may be corrected for the natural digestion ; and if 

 the excretion of metabolic products is found to follow general rules, then 

 it will become possible to calculate from the results obtained by artifi- 

 cial digestion the true coefficient of digestibility for the protein corre- 

 sponding with the coefficient obtained in experiments on animals. On 

 the basis of investigations commenced in Weende and continued for 

 the past 3 years at Gottingen, a method for accurately determining 

 these metabolic products has been perfected and the laws governing 

 the excretion of these products have been worked out. According to 

 the results obtained, for every 100 grams of dry matter digested 0.4 

 gram of nitrogen in the form of metabolic products is excreted, which 

 at present is reckoned as undigested protein. Eepeated experiments 

 have shown the method to be reliable, but have indicated that the excre- 

 tion of metabolic products is dependent upon two things, (1) the amount 

 of dry matter digested, and (2) the amount of undigested dry matter in 

 the food. The proportion of 0.4 j)art of metabolic nitrogen to 100 parts 

 of digested dry matter is therefore not infallible, but applies in general 

 where moderately concentrated feeding stuffs are used. The coeflicients 

 obtained by experiments in artificial digestion must therefore be recalcu- 

 lated to obtain results applying to animals. Thus the difference between 

 the percentage (63 per cent) of the protein in dried diffusion chips said 

 to be actually digested by ruminants and the coefficient (87 per cent) 

 indicated by artificial digestion, is said to be fully explained by the 

 metabolic products. 



The results of an experiment on the digestibility of oat straw showed 

 that the digestibility of the straw was very considerably increased 

 by treatment with a solution of sodium hydrate, for while 47 per cent 

 * Died November 22, 1890; succeeded by Prof. F. Lehmann. 



