470 



PHYSIOLOGY. 



Respiration Calorimeter. I follow the description of it by Bene- 

 dict. The apparatus at Middletown in its present form permits of the 

 measurements of the carbon dioxide and water vapor elimination, and 

 oxygen consumption, as well as the heat production, and it was believed 

 that the first extended use of the improved apparatus would best be a 

 study of inanition. 



The apparatus has been described in detail in Publication of the 

 Carnegie Institution of Washington, 42. 



"Since the apparatus and technique are not familiar to many, it 

 may be advisable to consider for a few moments some of its salient 

 points. The name 'respiration calorimeter' has been given this 



Fig. 1786. Horizontal Section of the Respiration Calorimeter. (BENEDICT.) 



n Portions shaded thus are of wood. A, Dead air space between Cu and 

 Zn walls. B, Dead air space between Zn wall and inside wood wall. 0, Dead air 

 space between inside and outside wood walls. D, Pneumatic air and heat insula- 

 tion packing. E, Food aperture tube, o o, Air-tight ports (glass). O, Outcom- 

 ing water. H, Ingoing water for absorbing heat. V, Ventilating air current. 



apparatus by Professor Atwater to indicate that it measures both 

 respiratory products and heat output. 



"Considering first the respiration features of the apparatus, it 

 may be said that the chamber itself consists of an air-tight copper 

 box, through which a ventilating current of air is caused to pass by 

 means of a rotary blower. This ventilating air current leaving the 

 chamber contains carbon dioxide and water vapor, and the oxygen con- 

 tent is somewhat diminished. The air is purified by first passing it 

 through sulphuric acid to absorb the water vapor, and second, through 

 soda lime to absorb carbon dioxide. The deficiency of oxygen is made 

 up by admitting oxygen from a cylinder of the highly compressed gas. 

 The air current is then caused to return to the chamber and is used 



