THE BALANCE OF NUTRITION 239 



and Reichert. 1 It is, however, not readily adapted for use with large 

 animals, both on account of the difficulty in determining the true 

 average temperature of a large mass of water and on account of the 

 great weight of such an instrument. 



The best known and most successful form of flow calorimeter for 

 experiments upon animals is that devised by Atwater and Rosa 2 and 



I 





FIG. 36. 



modified by Atwater and Benedict 3 for experiments on man and 

 adapted by Armsby and Fries 4 and by Hagemann 5 for experiments on 

 the larger farm animals. Figure 35 shows the general appearance of 

 the apparatus constructed by Armsby and Fries. 



The most familiar form of emission calorimeter is that of Rubner, 6 

 in which the changes in volume of the air enclosed between the double 

 walls of the animal chamber constitutes the indicator. Figure 36 

 shows the general appearance of the Rubner apparatus. A very 

 similar one has been devised by Rosenthal 7 in which the pressure of 

 the confined air at constant volume serves as the indicator. 



1 University Med. Mag., 1890, ii, 173. 



2 U. S. Dept. Agr., Office Expt. Stas., Bui. 63 (1899) ; Bui. 136 (1903). 

 8 Carnegie Institution of Washington, Publication No. 42 (1905). 



4 U. S. Dept. Agr., Bur. Anim. Indus., Bui. 51, (1903); and Experiment Station 

 Record, 15 (1903-1904), 1037. 



5 Landw. Jahrb., 41 (1911), Erganzbd. I. 



6 Ztschr. Biol., 30 (1894), 91- 7 Arch. (Anat. u.) Physiol., 1894, P- 223. 



