FOODS ANIMAL PRODUCTION. 



979 



subtracting from 100 the sum of the ether, alcohol, water, and acid 

 extracts and the liber. The acid and alkali extracts follow: 



The hydrochloric acid and alkali extracts of alfalfa. 



Acid extract: 

 Whole plant 



Leaves 



Stalks 



Alkali extract: 

 Whole plant 



Leaves 



Stalks 



Third 

 crop. 



Percent. 

 18.34 



22.14 



13.33 



17.62 

 'M. 17 

 13. 67 



Dilute hydrochloric acid would remove from the residue of material 

 extracted with water, starch and allied bodies and the hemicelluloses, 

 gluten and related substances, amins, and inorganic salts. Most of 

 these substances have a very high food value. 



"Nest to the crude fiber, the alkali extract is the most resistant portion of the 

 plant. It is made up chiefly of the insoluble nitrogenous bodies of the plant, 

 together with small quantities of carbohydrates, organic acids, and other sub- 

 stances. , . . 



"All the errors made in the preceding determinations fall upon the alkali extract. 

 In spite of this, duplicate determinations agree fairly well, and the results may be 

 accepted as indicative of the truth. . . . 



"The foregoing facts teach much of interest and importance concerning the con- 

 ditions of solubility of the alfalfa plant at its various stages of growth. We may 

 divide the constituents of a plant into 3 groups according to the solubility (leaving 

 out of consideration the fat): (1) Those easily soluble (in alcohol and water); (2) 

 those difficultly soluble (in dilute acids), and (3) those insoluble, or soluble only in 

 alkalis (fiber, and alkali-soluble). . . . 



"Considering the whole plant, during the early period more than one-third is 

 easily soluble, about one-third insoluble, and nearly one-quarter soluble with diffi- 

 culty. During the flowering period the easily soluble materials decrease to less 

 than one-third, the insoluble increase to nearly one-half, and the difficultly soluble 

 fall to less than one-fifth. During the late period the easily soluble portion 

 becomes less than one-fifth, the insoluble about two-thirds, and the difficultly 

 soluble less than one-eighth. 



"The easily and difficultly soluble portions of the plant may be considered almost 

 wholly digestible, while the insoluble portion is but slightly attacked by the diges- 

 tive juices. The percentage of insoluble and alkali-soluble material during the 

 flowering period is very nearly the same as the indigestible percentage as determined 

 by experiments with animals. Apart of the alkali-soluble portion, and of the crude 

 fiber is, of course, digested; and some of the materials of the soluble materials are 

 passed through the body without being digested. The decreasing solubility of the 

 plant with age is due almost wholly to the rapid accumulation of crude fiber. It is 

 quite certain that much of the soluble material becomes so entangled in the fiber as 

 to be practically indigestible. During the cutting periods for alfalfa it may be said 

 that about one-half of the plant is insoluble. 



"The leaves do not change very much. They are 10 per cent more insoluble when 

 old than they were when young. During the flowering period the leaves are as good 

 as a cattle food as at any other time. 



