102 AGRICULTURAL RESEARCH AND THE FARMER : 



of feeding can bs perfected, it is necessary to know with certainty 

 all the various stages by which food for the animal is built 

 up in the plant, and, a stage further on, broken down again in 

 the body of the animal to be rebuilt in the form of flesh or of 

 milk. In practice, this knowledge must be based upon a detailed 

 study of the composition of plant and animal fluids and juices, 

 such as urine, blood, &c., at various stages throughout the life 

 of the animal or plant. In the mangold, for example, the pro- 

 portionate amounts of the nitrogenous constituents of the root 

 vary according to the length of time the root has been stored, 

 a certain amount of nitrogen in a form unavailable to the animal 

 being converted, during storage, into an available form ; thus the 

 feeding value of the roots improves as the storage period increases. 

 It is clear, however, that before the whole " story " of the process 

 — from soil- water to plant juices and from plant juices to meat 

 and milk — can be written, a vast amount of chemical analytical 

 work m.ust be done, and that the rate of progress wiU depend 

 largely on the perfection of the methods adopted in the laboratory. 

 It is therefore satisfactory to be able to record the discovery 

 in the Cambridge laboratory of new simple and accurate methods 

 for the estimation of various organic constituents of plant and 

 animal juices. By the application of these methods it is now 

 possible to speed up the investigation of such processes as putre- 

 faction and fermentation, the rotting of manure, the quality of 

 meat and fish, the making of silage, the feeding value of agricul- 

 tural products in relation to maturity and conditions of storage, 

 &c. Already a good deal of work has been done on the question 

 of putrefaction and fermentation, in collaboration with an 

 eminent bacteriologist on the staff of the Medical School of the 

 University. 



Digestibility of Feeding Stuffs. 

 Another important question which closely affects the stock 

 feeder is the digestibility of the feeding stuffs supplied to his 

 stock. So far as the animal is concerned, it is not so much the 

 composition of the food which it eats that matters, as the propor- 

 tion which it can digest. An Animal Nutrition Research Institute, 

 therefore, must endeavour to provide the farmer with accurate 

 information regarding the digestibility of feeding stuffs. At 

 Carribridge much attention has been given recently to the question 

 of the digestibility of silage, and a brief outhne of the method em- 

 ployed may not be out of place. Little or no attention had hitherto 

 been given to this matter, although it is of obvious interest to deter- 

 mine how the digestibilities of the ingredients of silage compare with 

 those of the green crop from which it has been made, for without 



