INTRODUCTION. 1 3 



Food consumed and increase produced .... 265 



The experiments with sheep ..... 265 



The experiments with pigs ..... 269 



Composition of oxen, sheep, and pigs, and of their increase whilst 



fattening ....... 275 



Sources in the food of the fat produced in the animal body . . 284 



The experiments at Rothamsted with pigs . . . 288 



The experiments at Rothamsted with sheep . . . 305 



Summary on the sources of the fat of the animals of the farm . 312 



Food and milk production . . . . . .314 



Food and manure ....... 324 



Food and the exercise of force ...... 337 



Summary on the feeding of animals ..... 350 



Index ........ 355 



INTRODUCTION. 



The more systematic experiments at Eothamsted were com- 

 menced in 1843, so that 1893 was the fiftieth year of their con- 

 tinuance. In accordance with a request made by Mr James 

 Macdonald on behalf of the Highland and Agricultural Society 

 of Scotland soon after the celebration of the jubilee of the in- 

 vestigations in 1893, it is proposed to give in the following 

 pages such a general view of the half-century's work and results 

 as is practicable within the limits assigned to us ; but it will be 

 readily understood that it is no easy task to compress within 

 even the liberal space allotted to us anything like an adequate 

 account of the labours of a gradually increasing staff of workers 

 over a period of fifty years. This will be fully recognised when 

 it is borne in mind that the reports and other publications on 

 the results which have already appeared number about 120, and 

 that they occupy about 4000 octavo and more than 800 quarto 

 pages ; whilst there still remain considerable arrears of as yet 

 unpublished results. It is, in fact, from this mass of material, 

 published and unpublished, that selection has to be made in 

 endeavouring to give such a view of the objects, plan, and results, 

 of the investigations, as may be of value as illustrating the ad- 

 vance in knowledge acquired. 



Obviously, the scheme proposed precludes the idea of going 

 into full detail on any one subject, and supposes rather a com- 

 prehensive but at the same time only outline view of the whole. 

 The first question to consider is — Whether the illustrations relied 

 upon should have reference primarily to results obtained in the 

 field and in the feeding-shed, or chiefly to those of the laboratory 

 investigations ? As a prominent characteristic of the Eotham- 

 sted work has been the devotion of great attention to both field 

 and feeding experiments, and as by far the greater part of the 

 laboratory investigations, whether chemical or botanical, have 

 had for their object the solution of problems suggested by the 



