FOODS ANIMAL PRODUCTION. 



667 



Average dally income and outgo of nitrogen and carbon, with the estimated gain or loss of 



protein and of fat. 



Iii the following table is shown the daily income and outgo of protein 

 and energy in the same experiments: 



Comparison of daily income and outgo of protein and energy. 



These experiments and their bearing upon the problem of the con- 

 servation of energy in the animal body are discussed in some detail. 



"The differences between the income and outgo of energy as measured in these 

 two cases were 3.2 and 1.1 per cent, and averaged 2.2 per cent. The amount of 

 energy as measured was in each case less than the theoretical amount of potential 

 energy in the material consumed. The larger discrepancy was in the first experi- 

 ment. Certain sources of error in this appear to have been eliminated, at least in 

 part, in later experiments, of which ihe second was one. In these latter the agree- 

 ment is very close, the energy found being about 39 per cent of the theoretical. 

 On the whole the agreement between theoretical amounts of energy transformed 

 and those found in the experiments is as close as could be expected under the 

 circumstances. 



"It would be wrong to assume that these experiments demonstrate completely the 

 conservation of energy in the animal organism. They do, however, approach very 

 closely to such demonstration for the case of the man under experiment.'' 



Digestion experiments, ' F. E. Emery and B. W. Kilgore (North 

 Carolina Sta. Bui. 148, pp. 275-299). — In previous work of the station 

 (E. S. K., 3, p. 452 ; 4, p. 736 ; 5, p. 1081 ; 7, p. 702) it was found that when 

 cottonseed meal was fed with coarse fodders there was an increase in 

 the total amount of carbohydrates digested more than sufficient to 

 make up for the loss observed in the percentage of protein digested. 

 A number of experiments were therefore made with 4 sheep to deter- 

 mine the digestibility of timothy and crab-grass hay fed alone and with 



1 A bulletin bearing the same number and date, in which the detailed tables of the 

 digestion experiments were omitted, was also issued by the station. 



