166 



PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



in concentric layers, in which also the so-called gluten-cells are to be 

 recognized, as well as numerous free starchy granules. The relative 

 proportions of the different constituents vary in different samples, and 

 hence the nutritive value of these grains depends upon the method of 

 cultivation, etc. Corn and rye are especially rich in starch, but are 

 poorer than wheat in albumen. By soaking in boiling water, the only 

 way in which rice is used as a food, the starch-granules become par- 

 tially converted into soluble starch, through the rupture of the cellulose 

 membrane and solution of the granulose in water. So prepared, the 

 starch of corn and rice is capable of being entirely absorbed, while only 

 20 to 30 per cent, of the albuminous matter escapes. Barley and oats 

 are food-constituents which are especially valuable for horses when a 

 large amount of nutritive principles in a concentrated form is required. 

 R} T e is poorer in albuminous principles than wheat, but is, nevertheless, 

 a valuable food-stuff. From the point of view of the percentage of 

 albuminous matter, wheat occupies the first place in nutritive value of 

 the cereals. In 1000 parts 135.58 parts of albuminous matters are 

 present. The amount of starch of wheat is only exceeded by the carbo- 

 hydrates found in corn and rice. The following table, after Thanhoffer, 

 shows the amounts of these substances present in 1000 parts of the 

 principal cereals, leguminous plants, and tubers : 



From the above table it is seen that the amount of starch present 

 in rye is somewhat less than that of wheat, but that it contains nearly 

 twice as much dextrin ; and yet the cellulose, which is almost entirely indi- 

 gestible, is in larger amount than in wheat. In barley, again, there is usu- 

 ally a larger amount of albuminous matters than in wheat, but also three 

 times as much cellulose, and a considerably smaller amount of starch. 

 Barley grown in Southern latitudes is said to have a higher percentage 

 of albuminous matter than is represented above. Oats, again, contain a 

 smaller amount of albumen, a larger amount of cellulose, and a larger 

 amount of starch than barle}^. It thus falls considerably below wheat 

 in albuminous and starchy matters, but exceeds wheat in the amount 

 of cellulose present. Rape-seed, again, contains twice as much cellulose 

 as oats, and even less albumen than starch. Corn contains the smallest 



