174 PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



3. Bulbs and roots, represented by the potato, beets, etc., constitute 

 another group of vegetable foods. 



Potatoes are of very much less nutritive value than either of the 

 preceding groups of foods, from the fact that they contain but a small 

 amount of albuminous matters, but a very large amount of starch. Large 

 amounts of water are present in bulbs and roots which serve as food, with 

 small amounts of solids (86 to 14). Of the solids, the carbo-hydrates 

 constitute 80 per cent, or more, while the other nutritive substances 

 and inorganic salts are in proportionately small amount. Even of the 

 amount of albumen present only about one-fourth appears to be capable 

 of digestion in the alimentary canal. 



In the vegetables, such as beets, asparagus, and cabbages, there is a 

 large per cent, of water, — from 80 to 90 per cent., — but only 2 per cent, of 

 albuminous matter, 2 to 4 per cent, of starch or gummy substances, a 

 small amount of sugar, and 1 to 1.5 per cent, of cellulose. Their nutritive 

 value is therefore slight. 



Fodder-beets {Beta vulgaris, mangold-beets), of which a large variety 

 is met with, form valuable articles of fodder, those with the round roots 

 being usually more rich in nutritive constituents. The nutritive qualities 

 of beets are further increased by the character of the soil and climate, 

 mode of culture and manuring, and are especially proportional to the 

 slowness with which they are grown. Fodder-beets have, as a rule, the 

 following constituents : — 



Solids 12.0 per cent. 



Proteids, 1.1 



Fats 0.1 



Carbo-hydrates, 9.1 



Cellulose, 0.9 



Ash 0.8 



Sugar-beets contain — 



Solids 18.5 percent. 



Proteids, 1.0 



Fats, 0.1 



Carbo-hydrates, 15.4 



Cellulose, 13 



Ash, _ q'<7 



The principal difference, therefore, between fodder-beets and sugar- 

 beets, is found in the larger percentage of solids in the latter, consisting 

 principally in the greater amounts of sugar. The percentage of sugar 

 is further increased by potassium manures, and is greater in beets grown 

 in cold, high localities than in warm places. It also is in proportion to 

 the length of time, after growth is complete, that the beets are kept in 

 the ground, especially when they have sprouted. Nitrogenous manures 

 and manures rich in phosphates increase the proteid constituents of the 

 beets, although all the nitrogen in the beets is not to be recorded as 



