EXPERIMENT STATION RECORD. 



Vol. XV. April, 1904 No. 8. 



The record of respiration experiments abstracted in this issue is a 

 matter worthy of more than passing notice, both on account of the 

 unique character of the apparatus used and the evidence presented of 

 its application in fundamental studies on animal nutrition. Jt marks 

 a decided advancement in the method and facilities for such investiga- 

 tion, and it ma}' be said to represent the combined result of experience 

 in that important field. 



The respiration calorimeter itself, in its present form, is an Ameri- 

 can product. As is generally known, the Armsby-Fries apparatus 

 follows the Atwater-Rosa apparatus for experiments with man in its 

 main features of construction. In adapting the latter to experiments 

 with large animals, however, it was necessary not only to increase the 

 size of the respiration chamber but to introduce a considerable number 

 of special features, so that the operations of feeding, weighing, 

 collecting the excreta, etc., could be performed from without. The 

 cooperation of the subject within the chamber could not be counted on, 

 as in the case of experiments with man. Among the most interesting 

 of these special features are the devices for weighing the heat absorbers 

 from the outside, the air lock for introducing feed and water without 

 allowing the air in the respiration chamber to escape, and similar 

 devices for the collection of the liquid and solid excretory products. 

 As shown by the results of check experiments, the apparatus is ver}^ 

 accurate, the measured heat being practically identical with the theo- 

 retical amount produced by burning alcohol in the respiration chamber. 



In ordinary metabolism experiments the amounts and composition 

 of the food and of the urine and feces are the factors considered. 

 Using this apparatus the amount and composition of the respiratory 

 l)roducts, the fuel value of the food, and the energy output of the 

 body are also ascertained,, and it is possible to determine the total 

 income and outgo of both matter and energy. The sufficiency of the 

 ration and its digestibility are thus necessarily brought into account, 

 while the other data recorded make it possible to judge of the changes 

 going on in the body luuch more satisfactoril}^ than by any method 

 hitherto available. 



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