CHEMICAI, COMPOSITION AND FEEDING VALUE 1 69 



as they are deficient in protein and ash — hence, should 

 not be fed to growing cattle under two j^ears old, 

 lambs, or j^oung pigs, unless in very small amounts, 

 with other food to balance the ration. At Wisconsin 

 Experiment Station,' hogs ate cooked potatoes better 

 than uncooked, and 445 pounds of cooked potatoes were 

 equal to 100 pounds of corn-meal in feeding value. 

 One pound of dry matter of corn is superior to one pound 

 of dry matter of potatoes for making gains wdth pigs. 

 Cooking. — In cooking potatoes a considerable 

 portion of the albumen may be lost. Peeled potatoes 

 started in cold water lost 80 per cent, of albumen, 

 while those started in hot water lost but 10 per cent. 

 Less is lost if the potatoes are not peeled. Salt should be 

 added to potatoes, because the mineral matter they con- 

 tain is deficient in sodium salts, which are requisite for 

 the human system, and because salt increa.ses the pala- 

 tability. Varieties vary in the time they require to 

 cook, and even soil and climatic conditions have an 

 influence. In a floury, mealy potato the starch grains 

 have swollen and burst, and ruptured the cell-walls 

 surrounding them, while in a soggy potato this has 

 not taken place. Potatoes showing second grow^th 

 will not cook uniformly; the last-grown portion will 

 cook first. When second growth takes place the 

 starch passes from the older portion to the new^; hence, 

 when cooked, the older portion appears to be hard and 

 dark, while the newer portion is white and flour}', the 

 difference being due to the presence or absence of 

 starch. 



» Wis. Seventh Annual Report, 1890, and Henry, " Feeds and Feeding," 

 p. 212. 



