NITROGENOUS FOOD 299 



TABLE OF PERCENTAGE COMPOSITION or POULTRY AND FISH. (LETHEBY.) 



Water. Proteid. Fats. Salts. 



Poultry 74 21. 3.8 1.2 



White Fish 78 18.1 2.9 i. 



Salmon 77 16.1 5.5 1.4 



Eels (very rich in fat) 75 9.9 13.8 1.3 



Oysters 75.74 11.72 2.42 2.73 



The flesh of nearly all animals has been occasionally eaten, and we may 

 presume that except for difference of flavor, etc., the average composition 

 is nearly the same in every case. 



Milk. Milk is the entire food of young animals, and contains all the 

 elements of a typical diet. Albuminous substances are represented in the 

 form of caseinogen, and serum or lad albumin; fats in the cream; carbo- 

 hydrates in the form of lactose or milk-sugar; salts, chiefly as calcium phos- 

 phate; and water. From milk we obtain a number of food preparations such 

 as cheese rich in proteid and fat, butter and cream, buttermilk rich in proteids 

 and peculiarly well adapted for invalid diet, and whey which contains aH 

 the sugar salts- and the albumin. 



TABLE OF COMPOSITION or MILK, BUTTERMILK, CREAM, AND CHEESE. (LETHEBY 



AND PAYEN.) 



Nitrogenous 



Matters. Fats. Lactose. Salts. Water. 



Milk(Cow) 4.1 3.9 5.2 86 



Buttermilk 4.1 .7 6.4 .8 88 



Cream 4.1 26.7 2.8 1.8 66 



Cheese Skim 44-8 6.3 4.9 44 



Cheese Cheddar 28.4 31-1 4-5 36 



Eggs. The yolk and albumin of eggs of oviparous animals bear the 

 same relation as food for the embryos that milk bears to the young of mam- 

 malia, and afford another example of the natural admixture of the various 

 alimentary principles. The proteids of eggs are egg albumin and globulin, 

 of which the vitellin of the yolk is most important; nuclein in combination 

 with iron is also found. In addition to the three common fats there is a yellow 

 fatty pigment, lutein (lipochrome), lecithin, and cholesterin, a small quantity 

 of grape-sugar, and inorganic salts, chiefly potassium chloride and phosphates. 



TABLE OF THE PERCENTAGE COMPOSITION OF FOWLS' EGGS. 



Nitrogenous 



Substances. Fats. Salts. Water. 

 White 20.4 1.6 78 



Yolk 16. 30.7 1.3 52 



Legumes are used by vegetarians as the principal source of the nitrogen of 

 the food. Those chiefly used are peas, beans, lentils, etc.; they contain a 

 nitrogenous substance called legumin, allied to albumin. Legumes contain 



