FEEDING OF ANIMALS. 257 



to economise the expenditure of food in the mere mainten- 

 ance of the living meat-and-manure-making machine. As to 

 the use and adaptation of different foods, but little systematic 

 inquiry was undertaken in regard to it, each feeder relying 

 largely on his own judgment, or on the unwritten rules 

 adopted in his locality, as the result of practical experience. 



On the Continent, however, and especially in Germany, Contin- 

 much more attention was paid to the character of the food e ^J eed - 



X71Q TC~ 



than to that of the animal ; and towards the end of the last searches. 

 century and the beginning of this, much was devoted to deter- 

 mining the comparative value of different foods ; and tables 

 were constructed in which, adopting hay as the standard, it 

 was attempted to arrange all other foods according to their 

 supposed value compared with that standard. The plan was, 

 to give the amount of each food which it was estimated was 

 equivalent in food-value to 100 parts of hay. 



The first comprehensive tables of hay values were con- Thaer's 

 structed by Thaer, and were published by him in 1809. His hay values - 

 operations, experiments, and writings, were of an essentially 

 practical character. His estimates of so-called " hay values " 

 seem, however, to have been based to some extent on the de- 

 terminations of the supposed nutritive contents of different 

 foods which had been made by Einhof ; but partly also on 

 his own determinations, and partly on direct feeding experi- 

 ments. In these he sought to ascertain how much of the 

 respective foods was required to substitute a given quantity 

 of hay in the daily ration of the animals. His estimates were 

 at any rate controlled by such experiments, and he states that 

 their results upon the whole tended to confirm the conclusions 

 arrived at by analysis. 



Other writers also published tables of hay values, or hay 

 equivalents, of foods. In some of these the results of new 

 experiments, sometimes analytical, and sometimes practical, 

 were embodied; but it is obvious from the identity of the 

 figures in many cases, that they were largely compilations, 

 one from another. 



Such was the condition of knowledge on the subject when Boussin- 

 Boussingault commenced his investigation of it soon after ^ff^ ,n ' 

 1830. Like Thaer, Boussingault had the advantage of being tions. 

 a practical agriculturist ; but whilst Thaer looked at the 

 question of the feeding of the animals of the farm almost 

 exclusively from the practical point of view, Boussingault 

 approached it mainly from that of the chemist and the 

 physiologist, though he, at the same time, made direct ex- 

 periments with farm animals, and so arranged and conducted 

 them as not only to elucidate some points of special scientific 

 interest, but also to afford data which might serve both for 



VOL. VII. R 



