250 PRINCIPLES OF ANIMAL NUTRITION. 
Such computations have been made by different authors for the 
three principal classes of nutrients, viz., the proteids, carbohydrates, 
and fats, the results of a few of which are as follows: 
Bed _Zuntz.t | Kaufmann.t| Laulanié.§ 
‘Per | Per | Per | Per | Per |_Per | Per | Per 
Liter | Liter tse Liter | Liter | Liter rcun ond 
0. 0. 
Gall. | Cals. | Gals, | Cats. | Gals. | Cals. | Cals. | Cals. 
Proteids ||...........00.05 5.464|4.289|5.644/4.476'5 .569|4.647...... 4.6 
Waiticeja kt anaes oy Baan dae 6.586/4.676/6.628/4 .686,6.648/4.650 6.571/4.6 
Dextrose .............26../4.915/4.915]. 0.0.4.0... 5.056|5.056: 
Starch ss sacle acne da aves 4.976)/4.976|5.047|5.047 
Cane-sugar .............. 5.090|5 .090 
“Carbohydrates” ........].... Ba Mes aesars er are Peers | aerate 4.95 |4.95 
‘Kaufmann also computes from his theoretical equations already 
given in Part I (pp. 38 and 51) the evolution of heat per liter of 
oxygen in the various processes of partial oxidation which he be- 
lieves to take place in the body, with the following results: 
Albumen to fat and urea............... 4.646 Cals. 
ee “ dextrose and urea.......... 4.460 “ 
Fat (stearin) to dextrose............... 4.067 ‘ 
Disregarding the minor differences in the figures of different. 
authorities, it is evident that the amount of heat produced bears a 
much more constant relation to the oxygen consumed than to the 
carbon dioxide produced. For the fats and proteids, especially, the 
difference is comparatively small. In the case of an animal metab- 
* Arch. ges. Physiol., 55, 9, 
+ Ibid., 68, 191. 
} Archives de Physiol., 1896, pp. 329, 342, 757. 
§ Ibid., 1898, p. 748. 
|| As pointed out on pp. 74-75 the determination of the respiratory exchange 
corresponding to a unit of proteids is not a simple matter. In the table 
Kaufmann’s and Laulanié’s figures are based upon the theoretical equation * 
(p. 75) for the conversion of albumin into carbon dioxide, water, and urea, 
while those of Magnus-Levy and Zuntz are derived largely from determina- 
tions and estimates by Rubner (Zeit. f. Biol., 21, 363) and others of the 
proximate composition of the urine of meat-fed animals, As will appear 
later, these figures are not applicable to the urine of herbivora, 
