80 FEEDS AND FEEDING 



In every case milk rich in fat was less valuable per pound of dry 

 matter, fat included, than milk poor in fat, or even skim milk. Beach 

 reports that the pigs fed rich milk lost their appetites and were attacked 

 by diarrhea, finally not eating enough to sustain life, while those fed 

 skim milk or milk low in fat, throve. It should always be borne in mind, 

 however, that skim milk is low in the fat-soluble vitamine. (104) 



In Europe studies on infant feeding show that cow's milk rich in fat 

 tends to produce intestinal disturbances and is not so well adapted to 

 the needs of the human infant as poorer milk. The following explanation 

 of this harmful effect of excess of fat in the food of infants has been 

 offered: The general capacity of an animal for the absorption of fat 

 is strictly confined within narrow limits, and consequently any excess 

 is not absorbed but remains in the intestines. There it is converted into 

 soaps, which are formed by the combination of the fatty acids with such 

 alkalies as lime, soda, and potash. The soaps are excreted from the body 

 in the feces, bringing about a heavy loss of these alkalies. If this loss is 

 long continued, it results in disturbed nutrition. On an exclusive diet 

 of milk containing about 3.5 per ct. fat, the supply of alkaline bases 

 is only sufficient for normal development. Milk rich in fat does not 

 contain proportionally more of the alkaline bases, for man has bred 

 and selected cows only to meet the demands for more milk and for 

 that which is rich in fat. The eagerness with which calves sometimes eat 

 mortar, chalk, and other lime-containing substances points to the milk 

 being deficient in this respect. In such cases ground limestone or some 

 other form of lime should be supplied. 11 (685) 



118. Protein requirements for growth. As has been shown (11), the 

 individual proteins differ markedly in the amount of the various amino 

 acids they contain, and in some proteins certain amino acids are entirely 

 absent. Scientists believe that animals can construct in their bodies from 

 other nutrients but a very few of the different amino acids, and possibly 

 only the simplest one of all, called glycocoll. In the formation of the 

 protein tissues of the body all the various individual amino acids are 

 required, for the body proteins contain some of each of these building 

 stones. Hence for normal growth the protein in the food must supply 

 all of the necessary amino acids. \ The following illustration will show 

 the conditions the body may meet in forming body proteins from the 

 mixture of amino acids resulting from the digestion of the food protein : 

 Suppose we are building a brick wall in a certain pattern which requires 

 that 1 brick in 10 have a green end. If we are using as our source of 

 material a pile of bricks resulting from the tearing down of another 

 wall, in which only 1 brick in 50 had a green end, it is evident that we 

 will soon have to stop building, tho having many perfect bricks left, 

 because none has the green end required for the pattern. 



Some proteins, as the principal ones of wheat, yield on digestion as 

 much as 40 per ct. of a certain single amino acid, which forms only 14 



"Ernahr. landw. Nutztiere, 1907, p. 461. 



