174 BOARD OF AGRICULTURE. 



Experience also teaches us that some foods have higher feeding 

 values than others, and it is generally supposed that with a differ- 

 ence in feeding properties there will also be a difference in the 

 value of the manure. 



It is the province of agricultural chemistry to determine what 

 proportion of the several constituents of the food consumed will be 

 stored up in the form of meat, and how much will remain as 

 manure, according to the description of animal, and the kind 

 of food employed, and so to provide the means of estimating the 

 value of the respective products Of the feeding operation. To this 

 end, it is necessary to determine, by means of careful analysis, the 

 composition of the foods consumed, of animals in the store or lean 

 and in the fat condition, and of the manurial matters voided. 

 Such an undertaking is, however, by no means a light one, and it 

 can only be carried out with any prospect of success by the con- 

 joint aid of experiments on a large scale in the feeding-shed, and 

 of investigations in the laboratory, involving a great amount of 

 analytical labor, and requiring the observance of all the refine- 

 ments of method which modern science permits. 



I propose to bring before you a condensed summary of some of 

 the results which hav» been obtained in experiments made at 

 different times during the last twenty years, at my farm and 

 laboratory, at Rothamsted, in Ilertfordshire. There are, it is 

 true, many points which are not as yet satisfactorily cleared up, and 

 some of these are still under investigation. The figures given in 

 the tables, in most cases, however, represent the results obtained 

 in careful experiments with large numbers of animals of each of 

 the descriptions indicated, and they may be taken as showing 

 what should be the average result obtained in ordinary farm prac- 

 tice, when animals of fair quality are fed liberally for the butcher. 



Composniion of Oxen, Sheep and Pigs, in the Store and Fat Con- 

 dition. 



For the purpose of my illustration, I shall assume that an ox or 

 a sheep will increase in weight by about one-half, and that a pig 

 will double its weight during the so-called fattening period. Ac- 

 cordingly I shall direct your attention to the composition of each 

 of these descriptions of animal when in the lean or store, and also 

 when in the fat condition, after it has increased in the proportion 

 above supposed. I shall then show the average amount of food 

 required to produce 100 lbs. increase in live weight, and also the 



