158 FOODS 



foods combine to furnish in forms easily available to the as yet feeble 

 digestion the energy and the tissue demanded by the growing bones and 

 organs and muscles. It is easier to overdo the feeding of fats and of 

 carbohydrates than to underdo it, fat but "flabby" babies being often 

 supposed to be well nourished when in reality much less weight made 

 up of firm bones, solid muscles, and vigorous glands is of much greater 

 worth. The latter part of the third year is early enough to begin to give 

 to the child the general variety of always easily digested nutrients of the 

 adult diet. The limit of pro teid -feeding should be in its stimulating 

 effects on the preponderant nervous system of the child, the "beef -fed," 

 wheat-fed, and oat-fed boys and girls being, other things equal, those 

 with the best bodily start in life. Sugar should be, if possible, used very 

 sparingly, and in the form of candy given only immediately after meals. 

 As a muscle-energizer, sugar is unexcelled (page 383), but during the 

 first three or four years its use is apt to destroy the appetite for substan- 

 tial foods not so attractive to the taste. 



PREGNANCY AND LACTATION. A second physiological condition which 

 properly demands some qualitative adaptation of diet is that of preg- 

 nancy and lactation. In this case the changes from the average diet 

 required are very much less than in the feeding of infants, but they are, 

 nevertheless, of considerable importance. 



The fetus requires for its nourishment food which will furnish it espe- 

 cially with tissue, much kinetic energy not yet being required. This 

 nutriment it gets from the circulating proteids of its mother, largely 

 serum-albumin and serum-globulin. The mother needs, therefore, as 

 food an ample supply of both tissue-builders and energizers. The one 

 sort builds up the fetus, the rapidly growing uterus, mammary glands, 

 heart, and in general supplies the active anabolic functions characteristic 

 of pregnancy. The other, the energizers of the food, are necessary in 

 increased amount to supply the force the augmented work of the organ- 

 ism requires. Proteids of animal origin supply these materials better 

 than ony other nutrients, supplemented by a generous, abundant diet, 

 otherwise average in composition. During lactation a somewhat similar 

 excess of proteids over the average is apparently beneficial, together 

 with a normal excess of water. Milk is richest and most copious on 

 an abundant proteid diet, especially meat. Thereby also is solved the 

 problem of storing iron in the fetus in sufficient amount to last until solid 

 food begins to be taken, for milk is deficient in this essential element. 



SENILITY. In senility, or old age, the adaptation of diet qualita- 

 tively is, as in the other extreme of life, largely in the way of using 

 foods which are easily digested. Laxative and easily digested foods are 

 especially indicated 



IDIOSYNCRASY. The term idiosyncrasy (from a very similar Greek 

 word meaning peculiarity or temperament) is an interesting one in 

 physiology. Little is known, however, as to the causes and conditions 

 of these individual differences between persons. For our present purpose, 

 that is as concerns diet, the sense of the term is expressed very well by 



