CHEMICAL COMPOSITION. 



365 



falfa and also of the loss of nutritive properties 

 through exposure to the weather. We quote him 

 from Bulletin 155 : 



COMPOSITION OF ALFALFA HAY. 



As the amounts of moisture present in a hay are variable and 

 not a characteristic of the stage of maturity of the green plant, 

 a calculation of the results to a water-free basis is often advan- 

 tageous in making comparisons. Doing this for the three sam- 

 ples of alfalfa hay we get the following: 



COMPOSITION OF ALFALFA HAY CALCULATED TO A WATER-FREE BASIS 



Without going into the details of a discussion of the charac- 

 teristics of the groups of feed principles named in these tables 

 it may be useful to remind the reader of certain elementary 

 facts. 



The ash of a feeding-stuff is the residue left after burning all 

 combustible substances. For the most part this is derived from 

 the soil, though it may contain carbon that was secured from 

 the carhon-dioxid in the air. 



The crude protein embraces all organic compounds containing 

 nitrogen and may even include some inorganic nitrogenous sub- 

 stances. 



The pure protein is the crude protein minus certain nitrog- 

 enous substances that are less complex than proteins proper, 

 and possess a lower food-value. The proteins, by reason of the 

 nitrogen, sulphur and phosphorus which they contain, are en- 

 titled to greater esteem in a feed than are fats and carbohy- 

 drates. 



The crude fiber consists of cellulose and substances more or 



