. A text-book of physiology : for medical students and physicians . t calorim-etry really correspond with the heat obtained by direct measure-ment. In the hands of good observers the correspondence isvery close, and gives substantial proof of the scientific belief * For detailed accounts of special forms of air calorimeters see Rubner,Calorimetrische Methodik, 1891; and Rosenthal, Archiv f. Phvsiologie,1897, p. 170. CALORIMETRY. 951 that in the living body the energy liberated as heat or as heatand work is all contained in potential form in the foodstuffseaten. By means of the respiration calo
. A text-book of physiology : for medical students and physicians . t calorim-etry really correspond with the heat obtained by direct measure-ment. In the hands of good observers the correspondence isvery close, and gives substantial proof of the scientific belief * For detailed accounts of special forms of air calorimeters see Rubner,Calorimetrische Methodik, 1891; and Rosenthal, Archiv f. Phvsiologie,1897, p. 170. CALORIMETRY. 951 that in the living body the energy liberated as heat or as heatand work is all contained in potential form in the foodstuffseaten. By means of the respiration calorimeter we can obtain abalance between the energy income and outgo of the body as wellas between the material income and outgo,—that is, the carbon andnitrogen equilibrium. The most complete and elaborate form ofrespiration calorimeter used is that devised by Atwater and Rosafor experiments upon man.* The respiration chamber is a smallroom lighted and furnished so that an individual may remain init for long periods without discomfort. As shown in Fig. 301, this. SCALE I METER Fig. 301.—Horizontal section of respiration calorimeter. Portions shaded are of wood: A,dead-air space between Cu and Zn walls; B, dead-air space between Zn wall and inside woodenwall; C, dead-air space between inside and outside wooden walls; D, pneumatic-packing airand ;heat insulated; E, food-aperture tube; a, a, airtight ports (glass); H, ingoing water forabsorbing heat; G, outcoming water; V, ventilating air current. {Atwater and Benedict.) room is arranged as a calorimeter. It has several walls of metaland wood to prevent loss of heat to the outside or the reverse, andby means of water circulating through a system of pipes withinthe room the heat given up by the body is carried off. By regulat-ing this flow of water the temperature of the chamber can be keptconstant. Knowing the temperature of the water as it enters andleaves the chamber and the volume of the flow, the heat productionof the indiv
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