8 BULLETIN 649, U. S. DEPARTMENT OF AGRICULTURE. 
BUTTERFISH. 
Butterfish (Poronotus triacanthus) was chosen for one series of 
studies as an excellent fish of the type commonly used as pan fish. 
Butterfish occurs on the Atlantic and Gulf coasts from Maine to Texas, 
and during the year 1915 the catch of the coastal fisheries of New 
York and New Jersey amounted to over 5,000,000 pounds. At times 
it is taken in such abundance that a glut in the market results, and, 
since this fish is usually sold fresh, great quantities are wasted. The 
butterfish which was studied in the experiments here reported was of 
a good commercial grade, purchased in the local market, and it was 
believed to be representative of this type of fish procured under the 
ordinary trade conditions. 
The three subjects who assisted in the study of the digestibility of 
butterfish, following the same routine which has hitherto proved en- 
tirely satisfactory, ate an average of 105 grams of protein, 37 grams 
of fat, and 208 grams of carbohydrates, daily, the fuel value of the 
diet being 1,585 calories. The data obtained for the three-day test 
period are included in the following table: 
Data of digestion experiments with butterfish in a simple mixed diet. 
Weight 
of food. 
Constituents of foods. 
Experiment, subject, and diet. 
Water. 
Protein. 
Fat. 
Carbohy- 
drates. 
Ash. 
Experiment No. 452, subject D. G. G.: 
Butterfish (in form of fish loaf) 
Grams. 
1, 533. 
115. 
322.0 
1, 259. 
189.0 
Grams. 
1, 120. 9 
86.8 
22.2 
1, 065. 1 
Grams. 
303.7 
2.9 
26.1 
5.0 
Grams. 
74.5 
0.1 
43.1 
6.3 
Grams. 
Grams. 
33.9 
Potato 
Crackers '. 
Fruit 
Sugar 
24.0 
228.0 
178.8 
189.0 
1.2 
2.6 
3.8 
Total food consumed 
Feces 
3, 418.0 
46.0 
2,295.0 
337. 7 
22.8 
314.9 
124.0 
7.5 
116.5 
619.8 
11.3 
608 5 
41.5 
4.4 
Amount utilized 

37.1 
Per cent utilized 
93.2 
94.0 
98.2 
89.4 

Experiment No. 454, subject R. L. S.: 
Butterfish (in form of fish loaf) 
1,419.0 
139. 
355.0 
1,423.0 
163 
1,037.6 
104.9 
24.5 
1,203 8 
281.1 
3.5 
28.8 
5.7 
69.0 
0.1 
47.6 
7.1 
31.3 
Potato 
29.1 
251.3 
202.1 
163.0 
1.4 
Crackers 
Fruit 
Sugar 
2.8 
4.3 
3,499.0 
60.0 
2, 370. 8 
319.1 
24.9 
294.2 
123.8 
9.5 
114 3 
645.5 
16.5 
629.0 
39.8 
Feces ... 
9.1 
30.7 

Per cent utilized 

92.2 
92.3 
97.4 
77.1 
Experiment No. 455, subj^c 0. E. S.: 
1, 290. 
569.0 
122.0 
1,474.0 
196.0 
943. 2 
429.6 
8.4 
1,247.0 
255.6 
14.2 
9.9 
5.9 
62.7 
0.6 
16.3 
7.4 
2S.5 
Potato 
118.9 
86.4 
209 3 
196.0 
5.7 
Crackers 
1.0 
Fruit 
4.4 
Total food consumed 
Feces 
3,661.0 
68.0 
2,028.2 
285.6 
29.6 
256.0 
87.0 
14.5 
72.5 
610.6 
14.3 
596.3 
39.6 
9.6 
30.0 
89.6 
83.3 
97.7 
75.8 
Average food consumed per subject per day 
1,174.2 
810.5 
104.7 
37.2 
208.4 
13.4 
