Relative Value and Manurial Properties of Purchased Food. 651 



with oil-cake, if liay-ctaff is not at command, a certain amount of 

 tender straw-cliaff is almost indispensable. Young stock, however, 

 should not be supplied with food which is so poor in fibre-producing 

 substances, as straw is proved to be, and the English breeder seems 

 to have learnt this practical lesson from his own experience. 



But perhaps the maia reason why the English breeder and feeder of 

 stock excels foreigners so much is, that he is an emmenilij practical man, 

 who, by placing at difierent times all kinds of food, good, bad, and 

 indifferent, before his animals, has learnt by dint of sheer experience 

 what is best suited to them. On the continent, on the contrary, the 

 science of nutrition has been much more studied than the art of 

 feeding. Very little attention has been paid to practical feeding 

 experiments, such as those conducted so carefully and successfully by 

 Mr. Lawes of liothamsted, which are quite unique ; so that those 

 desiring information on the subject would do well to study the valuable 

 records of his experiments, as published from time to time in the 

 Society's Journal ; more especially his paper on pigs, which is quite 

 a model paper on experimental feeding. The art of feeding and 

 fattening stock is a peculiarly practical one, and can only be acquired 

 by practical experience. The scientific experimenter with precon- 

 ceived notions on the subject of nutrition is too apt to forget that he 

 has to deal with, not merely dead receptacles, but living creatiu-es, 

 with a nervous system, peculiarities of habit;, and an organism, which 

 must be considered at the very outset. The whole subject, however, 

 of nutrition is, and probably will continue to be, in a great measure, 

 enveloped in mystery; and so long as we cannot clearly establish 

 prhiciples applicable in every instance, it would be unwise to throw 

 overboard the results of actual farming exi^erience, and to fatten 

 according to the prevailing theories of the day. 



It may be instructive to examine the way in which continental 

 physiologists and agricultural chemists endeavour to get a deeper 

 insight into the chemistry of food, and the powers of animals to 

 assimilate flesh and fat, and so on. In studying the process of 

 nutrition, they proceed by supplying animals with what they con- 

 ceive to be enough food to keep them at their live weight ; they then 

 experiment with different kinds of food, the weight of which is 

 arranged according to its composition ; and from the results of the 

 weighings they derive general deductions, according to which they 

 estimate the value of the food. In England, on the contrary, even 

 in accurate feeding experiments, the plan is to put before the animals 

 an abundance of food of different kinds, to let them choose what 

 they will take, to ascertain afterwards what has been taken up in the 

 animal organism, and how much has passed into excreta, and then 

 deducting from the total amount of food the matters which remain 

 undigested, or have been altered in various ways in their passage 

 through the animals, the English experimentalist seeks to arrive at 

 some conclusion as to the value of the food usually given to cattle. 

 Now this plan appears to me by far the more rational. 



The chemistry of food has engaged the attention of many scientific 

 men. The literatm-e of the subject is very extensive ; and to chemists 



