4 BULLETIN 507, U. S. DEPARTMENT OF AGRICULTURE. 
portion ascribable to the fat supplied by the basal ration to' repre- 
sent the undigested portion of the fat studied. The significance of 
such values, in discussing problems of dietetics and the theoretical 
and other considerations having to do with metabolic products in 
feces, are fully discussed in earlier publications. 1 
DIGESTION EXPERIMENTS. 
CHICKEN FAT. 
Although chicken fat as such is not available in quantity in most 
markets the very large demand for poultry, especially mature poultry, 
would indicate a very considerable consumption of the fat along with 
the chicken meat. Little information, however, as to its digestibility 
and -nutritive value has been found in a survey of the literature. In 
studies of the digestibility of fish and poultry, Milner 2 found that 
chicken fat eaten as an integral part of poultry in a simple mixed diet 
was 97 per cent digested. 
Several pounds of chicken fat, which had been taken in small quan- 
tities from fat birds drawn at the market for those not desiring the 
excess fat, were procured. It was passed through an ordinary meat 
grinder and heated in a double boiler to a temperature higher than 
its melting point, after which the fat was easily separated from sur- 
rounding tissues by straining. 
For use in the digestion experiments the product was thoroughly 
mixed and incorporated in a blancmange or cornstarch pudding in 
the way previously described. Eight experiments of three days' 
duration were completed in which four normal subjects assisted. 
The results of these tests are recorded in the following tables : 
Data of digestion experiments with chicken fat in a simple mixed diet. 
Weight. 
Water. 
Pro- 
tein. 
Fat. 
Carbo- 
hydrates. 
Ash. 
Experiment No. 274, subject H. F. B.: 
Grams. 
2,357.0 
545.0 
1, 549. 
192.0 
Grams. 
1,072.0 
49.0 
1,346.1 
Grams. 
45.7 
57.8 
12.4 
Grams. 
359.7 
8.2 
3.1 
Grams. 
863.6 
421.3 
179.7 
192.0 
Grams. 
16.0 
8.7 
Fruit 
Sugar 
4,643.0 
148.0 
2, 467. 1 
115.9 
44.4 
71.5 
371.0 
26.4 
344.6 
1,656.6 
65.0 
1,591.6 
32.4 
12.2 
20.2 
Per cent utilized 
61.7 
92.9 
96.1 
62.3 
Experiment No. 275, subject D. G. G.: 
Blancmange containing chicken fat 
1,597.0 
396.0 
492.0 
158.0 
726.3 
35. 7 
427.5 
31.0 
42.0 
3.9 
243.7 
5.9 
1.0 
585.1 
306.1 
57.1 
158.0 
10.9 
Wheat biscuit 
6.3 
Fruit 
2.5 
Total food consumed 
2, 643. 
88.0 
1,189.5 
- 76.9 
26.2 
50.7 
250.6 
15.6 
235.0 
1, 106. 3 
40.1 
1,066.2 
19.7 
6.1 
13.6 
65.9 
93. S 
96.4 
69.0 

i U. S. Dept. Agr., Office Expt. Stas. Buls 126 (1903), pp. 18-20; 193 (1907), pp. 47-59; Connecticut Storrs 
Sta. Rpt. 1896. pp. 178-180. 
2 Connecticut Storrs Sta. Rpt. 1905, pp. 135, 136. 
