334 



BOARD OF AGRICULTURE. 



Summary and Discussion of Digkstion Experiments. 



Below can be seen, brought tojrether in one table, the percentages 

 or coefficients of digestibilit}' as determined from the data of the 

 preceding experiments. 



Dry Substance 



Organic Matter 



Protein 



Crude Fiber 



Nitrogen-free Extractive Matter 

 Fat 



The above figures are the answers to actual inquiries made of the 

 animal as to the availability of the ingredients of the several foods 

 for the purposes of nutrition. The meaning of these figures is plain. 

 They mean, in the case of the clover haj" for instance, that of each 

 hundred pounds of dry substance fed 54.4 pounds were dissolved out 

 by the digestive fluids, and that 45.6 pounds passed out of the ani- 

 mal unused, or that of each 100 pounds of crxide fiber in the hay, 

 only 46.2 pounds were retained for use in the animal bod}'. Except 

 for the protein and fats, the above figures are undoubtedly' a 

 close approximation to what they should be, the small error in- 

 volved being relativel}' the same in all cases. The percentages given 

 for the protein and fats are too small, the relative error in this direc- 

 tion being greater the less the quantit}' of protein and fat in the 

 foods. {T\iQ nature and extent of these errors are discussed later.) 

 For instance, the protein of the Timothy ha}- appears to be much less 

 digestible than the protein of the clover hay. SuflScient facts are 

 well established to warrant the statement that part of this difference 

 at least is apparent rather than real, from the fact that as the Tim- 

 othy hay contains but little over half as much protein as the clover 

 hay, the percentage error in determining the digestibility of this in- 

 gredient is much larger in case of the Timothy. 



