THE PBOGh'ESS OF SCIENCE. 



187 



u 



Meter Pump and Absorption Tubes (Armsby-Fries Apparatus). 



metabolism experiments with animals 

 the amounts and composition of the 

 food and of the urine and feces are the 

 factors considered. Using this ap- 

 paratus it is possible to determine the 

 total income and outgo of both matter 

 and energy. The apparatus affords 

 opportunity for investigation in a great 

 variety of important lines, and for 

 checking the results secured by the 

 more practical feeding experiments. 

 It is especially adapted to studies of 

 such questions, for example, as the 

 energy required to digest and assimi- 

 late different classes of feeding stuffs, 

 the food requirements of animals under 

 different conditions, and the replacing 

 value of nutrients. 



An experiment recently reported with 

 the apparatus, the first one to be pub- 

 lished, was on the available energy of 



timothy hay. In this a large steer 

 was used, and there were four periods, 

 each covering two days in the respira- 

 tion chamber. This first experiment 

 gave results of much interest from both 

 a scientific and a practical standpoint, 

 and clearly demonstrates that for 

 studies on the nutrition of animals, 

 as well as of man, the possible lines of 

 investigation with the respiration 

 calorimeter range from the most prac- 

 tical to the most technical subjects. 



It is worthy of mention that the 

 Armsby-Fries apparatus is a distinctly 

 American product, and is the only one 

 of its kind in operation in the world. 

 A similar apparatus, modeled after it, 

 is being constructed at the agricultural 

 academy in Bonn, C4ermany, but is not 

 yet in operation. 



