SCIENTIFIC FARMING AT ROTHAMSTED. 395 



DESCRIPTION OF ANIMALS. 



Store, lean and half -fat animals 



Store sheep 



Store pig 



Half-fat ox 



Half-fat old sheep 



Fat and very fat animals : 



Fat calf 



Fat ox 



Fat lamb 



Fat sheep 



Very fat sheep 



Fat pig 



Means : 



Store and half-fat animals . . . 



Fat and very fat animals 



Of the ten animals analyzed. . 



For comparison with these ratios of the nutritive constituents of 

 animal foods, wheat-flour hread was selected as one of the most im- 

 portant of the representative articles of vegetable food. The fat in 

 the bread itself, estimated at one per cent, which is probably above the 

 average, was reckoned in its equivalent of starch, and the ratio of ni- 

 trogenous and non-nitrogenous constituents was then found to be 1 to 

 6*8. Of the animals fattened for the butcher's use, the fat calf, only, 

 gives a smaller proportion of non-nitrogenous constituents than the 

 bread ; the fat ox has nearly the same, and the other animals very 

 much more. The averages also show that beef, mutton, and pork, on 

 the whole, are not deficient in carbo-hydrates or non-nitrogenous nu- 

 tritive constituents. After a full discussion of the subject, Drs. Lawes 

 and Gilbert come to the conclusion that the great advantage of a 

 mixed bread and meat diet, over one of bread alone, does not depend 

 on the nitrogenous substance, but rather in substituting fat for a por- 

 tion of the starch of vegetables. From the greater value of fat as a 

 source of energy, and the general advantages of a variety of nutritive 

 elements in the composition of a diet, this view of the influence of 

 animal food seems to be well founded. 



The limits of this article will not allow us to notice the experiments 

 with sewage, and the feeding value of sewage-grown crops in the pro- 

 duction of meat and milk ; or the milling products of grain grown 

 under a variety of conditions, and other special subjects of investiga- 

 tion, that have been included in the work at Rothamsted.. 



It is perhaps worthy of notice that nitrogen was the prominent 

 object of interest in the Rothamsted field experiments, whilo the 

 carbo-hydrates or non-nitrogenous constituents of the food seemed to 



