606 EXPERIMENT STATION EKCOKD. 



students. The establishment of experiment stations throughout 

 Japan and the introduction of commercial fertilizers in that country 

 are attributed largely to his efforts. 



Following his twelve year^ in Japan, in 1893 he was appointed 

 director of the Mockern Experiment Station to succeed Gustav Killin, 

 who had died the previous year. The eighteen years which followed 

 Avas the period in his life which made him famous as a leader in the 

 advanced theories of animal nutrition. He brought to his work a 

 thorough preparation, a keen perception, and an energy and perse- 

 verance which were the foundations of his success. 



His first undertaking w^as to compile and publish the w^ork left by 

 his predecessor, covering a period of nearly twenty years and repre- 

 senting a large part of the life work of this eminent investigator. 

 This summary was issued in 1894, occupying an entire volume of Die 

 landicirtschaftlu'hen Versuchs-jStationen, nearly six hundred pages. 



Kiihn had followed in the lines of Henneberg and Stohmann in 

 employing the respiration apparatus to study the utilization of feed- 

 ing stuffs under different conditions. Kellner supplemented the res- 

 piration experiments with calorimetric determinations of the energy 

 A^alue of the feeds employed and of the animal excreta, in accordance 

 with the teachings of Ilubner, and by this means established nutritive 

 values for many feeding stuffs and their individual constituents. As 

 subjects he employed full-grown steers and oxen, and later milch 

 cows, while Zuntz studied in a similar way the nutrition of the horse. 



This new point of view, which involved the study of the metabo- 

 lism of both matter and energy under different conditions of feeding, 

 resulted in marked advance in the theory of nutrition. It showed 

 that like amounts of digestible nutrients in different feeds have differ- 

 ent values and that the energy required for digestion and losses due 

 to decomposition, etc., must be taken account of in arriving at the net 

 or available values. This conception of the gross energy as having a 

 varying net value furnished the basis for a new means of estimating 

 net values of feeding stuffs, and upon this basis Kellner worked out 

 his system of " starch values " as a means of comparing feeds and cal- 

 culating rations. 



Kellner's investigations on the metabolism of matter and energy in 

 cattle covered seventeen years of work axid included both maintenance 

 and fattening conditions. He also studied the energy and nutrient 

 requirements as a basis for the refinement of the feeding standards, 

 and determined the digestibility of numerous materials and the action 

 of the individual nutrients. A long list of new feeds was studied, 

 including the molasses preparations; and his experiments were ex- 

 tended to milch cows to determine the action in milk production of 

 various classes of feeds. 



