484 
Journal of Agricultural Research 
Vol. XXXI, No. 5 
These defects have seriously affected the general character, as to 
accuracy, of the existing evidence in the fidd of net-energy deter¬ 
minations. 
Two procedures have been used in computing net-energy values, 
and have been widely quoted. Both are correct in principle, but 
tend to magnify experimental errors. 
In the earlier metnod the net-energy value of a feed was determined 
by comparison of the gains in energy yielded by rations of different 
amounts. The feed represented in the computation was only the 
difference between the two rations, the relatively extensive mainte¬ 
nance requirement of net energy not being directly involved, the 
effect, therefore, being to relate the entire error of the determination 
to the small amount of feed represented by the gain. 
The later method is an improvement over the earlier one in that 
the above-mentioned exaggeration of errors is eliminated. It tends, 
however, to obscure the individuality of the data, and to exaggerate 
the effects of assumptions necessarily involved. 
A revised method of computation of net-energy values is presented 
which tends to eliminate the exaggeration of errors and to preserve 
the individuality of the data, and makes possible the computation 
of a net-energy value of a feed for each of a series of periods, instead 
of giving only one average value representing results of two or more 
periods, as accomplished by the earlier methods. It thus also pro¬ 
vides an improved basis for judgment as to the consistent character 
of an experiment as a whole. 
LITERATURE CITED 
(1) Armsby, H. P., and Fries, J. A. 
1903. THE AVAILABLE ENERGY OF TIMOTHY HAY. U. S. Dept. Agr., Bur. 
Anim. Indus. Bui. 51, 77 p., illus. 
(2) -and Fries, J. A. 
1905. ENERGY VALUES OF RED CLOVER HAY AND MAIZE MEAL. U. S. 
Dept. Agr., Bur. Anim. Indus. Bui. 74, 64 p., illus. 
(3) -and Fries, J. A. 
1908. THE AVAILABLE ENERGY OF RED CLOVER HAY. U. S. Dept. Agr., 
Bur. Anim. Indus. Bui. 101, 61 p., illus. 
(4) -and Fries, J. A. 
1911. THE INFLUENCE OF TYPE AND OF AGE UPON THE UTILIZATION OF 
feed by cattle. U. S. Dept. Agr., Bur. Anim. Indus. Bui. 
128, 245 p., illus. 
(5) -and Fries, J. A. 
1915. NET ENERGY VALUES OF FEEDING STUFFS FOR CATTLE. Jour. Agr. 
Research 3: 435-491, illus. 
(6) - Fries, J. A., and Braman, W. W. 
1916. ENERGY VALUES OF RED-CLOVER HAY AND MAIZE MEAL. Jour. Agr. 
Research 7: 379-387. 
(7) -and Fries, J. A. 
1917. ENERGY VALUES OF HOMINY FEED AND MAIZE MEAL FOR CATTLE. 
Jour. Agr. Research 10: 599-613. 
1917. the nutrition of farm animals. 743 p., illus. New York. 
(9) -and Fries, J. A. 
1918. NET ENERGY VALUES OF ALFALFA HAY AND OF STARCH. Jour. Agr. 
Research 15: 269-286. 
(10) Fries, J. A., and Kriss, M. 
1924. METABOLISM OF CATTLE DURING STANDING AND LYING. Amer. Jour. 
Physiol. 71: 60-83. 
(11) Kriss, M. 
1925. A COMPARISON OF DIRECT AND INDIRECT CALORIMETRY IN INVESTI¬ 
GATIONS with cattle. Jour. Agr. Research 30: 393-406. 
