34 MAKUAL OF CATTLE-KEEJDmG. 



siieli as are retained, owing to tlieii^ small size, escape mas- 

 tication and are not digested. 



Tlie proportion of albuminoids in the same species of 

 plants and in the same parts of the plant differs according 

 to the quality of the soil on which it is grown, the manur- 

 ing, the weather, and other circumstances, so that it is only 

 by means of numerous analyses that the average composi- 

 tion of any fodder can be ascertained. A discussion of 

 these points and of the results of analyses of the more im- 

 portant fodders will be found in Part II. 



Other Niteogenous Constituents of Plants. — ^Vari- 

 ous nitrogenous substances not belonging to the albumi- 

 noid group have been found in plants. For our present 

 purpose, we may divide them into f oxir classes : 



1. Witrates^ nitrites^ and ammonia salts; 



2. Peptones; 



3. Alkaloids; 



4 Ami7ies^ amides^ and amido-acids. 



Nitrates, Nitrites, and Anunonia Salts. — These sub- 

 stances usually occur very sparingly in plants, though beets, 

 and probably other root crops, contain considerable quan- 

 tities of them, and maize also frequently eontahis a liot in- 

 considerable amount of nitrates. These substances, how- 

 ever, need hardly be taken into account here, since they 

 have no imtritive value. 



Peptones. — Eecently, v. Gorup-Besanez has shown (i?<?n 

 Peut Clmn, Gm,^ 1874, p. 1478) that the seeds of the vetch 

 contain a ferinent capable of converting starch into sugar 

 and albuminoids into peptones,* and a similar substance has 

 since been found in other seeds. It is highly probable that, 



* Bee p 59. 



