THE RESPIRATION CALORIMETER AT THE PENNSYLVANIA 

 EXPERIMENT STATION. 



H. P. ARM8BY, Ph. D., LL. I)., 

 Director Pennsi/lrania Experiment Station. 



Our present methods of investigating- tlie prolilenis of stock feeding 

 are still ver}- largeLy based upon the classic inxestigations of Henne- 

 berg and Stohniann at the \Yeende Experiment Station, covering 

 approximately the years from 1858 to 1870. Beginning with investi- 

 gations upon the digestibility of feeding stuH's and upon the mainte- 

 nance requirements of farm animals, they subseciuently took up more 

 complex problems. A respiration apparatus modeled after that of 

 Pettenkofer at Munich was constructed, and somewhat extensive 

 respiration experiments with both cattle and sheep were conducted. 

 No more carefully thought out, complete, and logical programme for 

 investigations in animal nutrition is on record than that written by 

 Henneberg in 1868 and published in 1870 as an introduction to his 

 "Neue Beitriige.''" This paper outlines the general features of the 

 problem and will well repay careful perusal by every student of the 

 subject. 



Such investigations as Henneberg mapped out, however, are neces- 

 sarilj" slow and expensive, particularly- in the case of farm animals, 

 and while the respiration apparatus found extensive use b}- the ph3^si- 

 ologists for smaller animals, investigators of feeding pi'oblems were 

 largely content for many years with the simpler methods of digestion 

 and metabolism experiments. It is only quite recently that the inves- 

 tigations of Kiihn and Kellner at Moeckern and of Zuntz and Hage- 

 mann at Berlin have aroused new interest in these fundamental 

 (|uestions. In the United States the work of the experiment stations 

 has almost of necessit}^ been along lines similar to those pursued for 

 many years abroad. While the investigations of our stations have 

 done much to advance our knowledge of the subject of stock feeding, 

 especially' as related to questions of practice, the}- have at the same 

 time made increasingly evident the need for more scientific study of 



« Ueber das Ziel nnd die Methoden der auf den Landwirth.«chaftlichen Yersuchs.sta- 

 tionen auszufiihrendeu thier-]jliysiologischen Untersuchungen. 



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