DIGESTIBILITY OF MISCELLANEOUS ANIMAL FATS. 
11 
composite fat taken from different parts of the body. Through the 
courtesy of Superintendent Hollister, of the National Zoological 
Park, a supply of horse fat (neck and leaf) was secured from a 
healthy inspected animal, such as are regularly procured to supply 
food for the carnivorous animals confined in the park. In the un- 
rendered form its physical appearance was so similar to that of beef 
fat that the members of the laboratory staff who were unaware of its 
source assumed it to be beef fat. Samples of the neck and leaf fats 
which were analyzed by R. H. Kerr, of the Bureau of Animal In- 
dustry, were found to have the following constants : Neck fat, iodin 
number 95.83 and refractive index at 40° C. 55.5° and leaf fat, iodin 
number 91.22 and refractive index at 40° C. 54.0°. The unrendered 
fats were passed through a meat cutter, uniformly mixed, and ren- 
dered in a double boiler. The rendered fat on standing tended to 
separate into an oily and solid layer, resembling chicken fat in this 
respect. 
Three subjects assisted in the experiments, which are reported in 
the tables which follow : 
Data of digestion experiments with horse fat m a simple mixed diet. 
Weight 
of foods. 
Constituents of foods. 
Experiments, subjects, and diet. 
Water. 
Protein. 
Fat. 
Carbohy- 
drate. 
Ash. 
Experiment No. 747, subject P. K.: 
Grams. 
1,634.0 
304.0 
514.0 
265.0 
Grams. 
734.2 
27.4 
446.7 
Grams. 
33.0 
32.2 
4.1 
Grams. 
184.0 
4.5 
1.0 
Grams. 
669.1 
235.0 
59.6 
265.0 
Grams. 
13.7 
Wheat biscuit 
4.9 
Fruit 
2.6 
Sugar 
Total food consumed 
2,717.0 
67.0 
1,208.3 
69.3 
22.3 
47.0 
189.5 
9.4 
180.1 
1,228.7 
29.9 
1,198.8 
21.2 
Feces 
5.4 
Amount utilized 
15.8 
Per cent utilized 
67.8 
95.0 
97.6 
74.5 
Experiment No. 748, subject M. L. M.: 
1,670.0 
558.0 
667.0 
429.0 
750.3 
50.2 
579.6 
33.7 
59.2 
5.4 
188.1 
8.4 
1.3 
683.9 
431.3 
77.4 
429.0 
14,0 
Wheat biscuit 
8.9 
Fruit 
3.3 
Total food consumed 
3,324.0 
133.0 
1,380.1 
98.3 
40.8 
57.5 
197.8 
13.2 
184.6 
1,621.6 
68.3 
1,553.3 
26.2 
Feces 
10.7 
Amount utilized 
15.5 
58.5 
93.3 
95.8 
59.2 
Experiment No. 749, subject J. C M.: 
Blancmange containing horse fat 
1,719.0 
385.0 
948.0 
194.0 
772.4 
34.6 
823.8 
34.7 
40.8 
7.6 
193.6 
5.8 
1.9 
703.9 
297.6 
110.0 
194.0 
14.4 
Wheat biscuit 
6.2 
Fruit 
4.7 
Sugar 
Total food consumed 
3,246.0 
123.0 
1,630.8 
83.1 
37.4 
45.7 
201.3 
15.3 
186.0 
1,305.5 
59.8 
1,245.7 
25.3 
Feces r 
10.5 
Amount 
14.8 
Per cent utilized 
55.0 
92.4 
95.4 
58.5 
Average food consumed per subject per day . . , 
1,032.0 
468.8 
27.9 
65.4 
461.8 
8.1 
