FEEDING OF ANIMALS. 305 



fat must have its source in other constituents than the fat 

 and nitrogenous substance of the food — in other words, in the 

 carbohydrates. 



The Experiments at Rothamsted with Sheep. 



It has been pointed out that, compared with pigs, there is Experi- 

 with ruminants a much smaller amount of increase obtained, X^fe*** 

 in proportion both to their weight within a given time, and conclusive. 

 to a given amount of food passed through the body ; that 

 there is also a much larger amount of necessarily effete 

 matter in their food ; and that, therefore, the result of cal- 

 culations of feeding experiments with them in regard to 

 the question of the sources in the food of the fat stored up 

 in the body are less conclusive. It will, nevertheless, be of 

 interest to adduce some direct experimental evidence on the 

 point. 



Some time after the discussion at Hamburg in 1876, two Rotham- 

 sets of experiments made at Eothamsted with sheep, in which ^^tTrnth 

 the concentrated foods were barley or malt, and in which, sheep. 

 therefore, the amount and proportion of nitrogenous sub- 

 stance consumed was low, were selected for calculation. 



The first series comprised five pens, with four or five sheep 

 in each. The experiments had been made in the spring of 

 1849, and extended over a final fattening period of ten 

 weeks. In each pen barley or malt was given in fixed 

 quantity per head per day, and in each mangels were given 

 in addition, ad libitum. 



The second series also comprised five pens, but with twelve 

 sheep in each. The experiments were made in the winter 

 of 1863-64, and they extended over a final fattening period 

 of twenty weeks. The animals were at an earlier stage of 

 progress at the commencement, and not quite so mature at 

 the conclusion, as those of the other series. In each pen 

 barley or malt was given in fixed quantity per head, in each 

 clover-chaff also in fixed quantity, and in each roots were 

 given ad libitum — Swedish turnips during the first sixteen 

 weeks, and a mixture of one-fourth swedes and three-fourths 

 mangels during the last four weeks of the twenty. 



The results of these two series of experiments with sheep, 

 calculated to show their bearing on the question of the 

 sources of the fat stored up by the animals, are given in 

 Table 72. 



It will be seen that the form of the table is, so far as the TabUil 

 facts will allow, the same as has been adopted in the case ex P lained - 

 of the various experiments with pigs. A general descrip- 

 tion of the food of each series is given over the columns 



VOL. VII. U 



