7 



the entire bodies, of ten animals, namely, one calf, two oxen, one lamb, 

 four sheep, and two pigs. Complete analyses of the ashes, respectively, 

 of the entire carcasses, of the mixed internal and other " offal " parts, and 

 of the entire bodies, of each of these ten animals, have also been made. 



From the data provided as just described, as to the chemical compo- 

 sition of the different descriptions of animal, in different conditions as to 

 age and fatness, the composition of the increase whilst fattening, and the 

 relation of the constituents stored up in increase to those consumed in 

 food, have been estimated. To ascertain the composition of the ma- 

 nure in relation to that of the food consumed, oxen, sheep, and pigs 

 have been experimented upon. The loss or expenditure of constitu- 

 ents, by respiration and the cutaneous exhalations, has not been deter- 

 mined directly, but only by difference, that is, by calculation, founded 

 on the amounts of dry matter, ash, nitrogen, etc., in the food, and in the 

 (increase) fceces, and urine. 



Independently of the points here enumerated, the results obtained 

 have supplied data for the consideration of the following questions : 



1. The characteristic demands of the animal body, for nitrogenous or 

 non-nitrogenous constituents of food, in the exercise of muscular power. 



2. The sources in the food of the fat produced in the animal body. 



3. The comparative characters of animal and vegetable food in human 

 dietaries. 



Having given a brief outline of the scope and plan of the investiga- 

 tions that have been in progress at Rothamsted for so many years, I 

 propose to draw my illustrations as to the character and significance of 

 the results obtained, mainly from those relating to the growth of wheat 

 for more than forty years in succession on the same land : 



1. Without manure. 



2. With farm-yard manure. 



3. With a great variety of chemical manures, both individual con- 

 stituents and mixtures. 



Table I. gives the number of bushels of dressed grain per acre without 

 manure, and with farm-yard manure, in each of the forty years, 1844 to 

 1883 inclusive; and on some of the artificially manured plots, mainly 

 selected to illustrate the effects of exhaustion and of manure-residue. In 

 most cases in this table, and in all cases in the subsequent tables, the 

 results obtained on the artificially manured plots are only given for the 

 last thirty-two of the forty years, as during the first eight years the ma- 

 nures were not the same year after year on the same plot as they were 

 subsequently. 



FIRST. WITHOUT MANURE. 



After a five-course rotation since manuring (turnips, barley, peas, 

 wheat, oats), the first experimental wheat crop was harvested in 1844. 

 The highest yield of the series was 23^ bushels in 1845, and the lowest 



