INVESTIGATIONS ON THE METABOLISM OF MILCH COWS. 909 



tbe digested material. This is the value assumed for pigs fed rice. 

 This value aud other data can he calculated for swine by comparing 

 MeisslV work on the formation of fat in pigs when rice is fed with the 

 values obtained in metabolism experiments with fasting swine. 



One of the pigs weighed 71 kg. and was fed 2,000 gm. of rice daily. 

 Ten liters of water and 10 gm. of salt were given in addition. The rice 

 had the following percentage composition: Water 13.13, nitrogen 1.09, 

 carbon 39.29, protein 6.81, fat 0.82, starch 78.7G, crude fiber 0.09, and 

 pure ash 0.39. The materials consumed in the food and excreted in 

 the feces, urine, and respiratory products, and gained by the body per 

 day are shown in the following table: 



Metabolism experiment with pigs. 



The protein, fat, and crude fiber digested contained in round numbers 

 09.2 gm. of carbon. The total digested carbon of the food was 706.2 

 gm. Therefore starch must have furnished 697 gm. (766.2 — 69.2 = 697). 

 The 48.6 gm. of protein gained contained 25.8 gm. of carbon and the 

 12.1 gm. of fat contained 9.3 gm. of carbon. Since the total carbon 

 gained was 339.2 gm., 291.1 gm. must have been obtained from starch, 

 and must have been retained as fat. It follows that each gram of 

 digestible carbon from starch furnished 0.422 gm. of carbon for the 



formation of fat ( ^ 1( . ~ = 0.422 j. There was excreted in the breath 



21.4 gm. of carbon dioxid per kilogram of weight ( -q 7 V = 21.4 J, 2 



which would contain 15.564 gm. of oxygen; 10.3 gm. of nitrogen was 

 excreted in the uriue, and 0.906 gm. of protein was broken down per 



X 6.25 = 0.006 ). As noted above, this 



/T0.3 

 kilogram of body weight ( -fjr- 



would require 1.23 gm. of oxygen (1.358x0.906 = 1.23), and would 

 produce 1.36 gm. of carbon dioxid (1.507 x 0.906 = 1.36). There was 

 stored up as fat 294.1 gm. of carbon from starch; therefore, the 

 fat formed from starch per kilogram of live weight was 5.421 gm. 



\ — 76 r 4 x 71 = ,r> - 412 )• As previously noted, when 44 gin. of fat 



1 Ztschr. Biol., 22 (1886), p. 84. 



a CO, : C =44 : 12 = 11.3. Therefore C X 



11 



CO, 



