122 FOOD 



above the temperature of 100 (212 F.) ; but this may penetrate 

 throughout the whole substance of the meat, producing a uniform 

 decolorization. Notwithstanding the coagulation of the albuminous 

 liquids by boiling, the fibrous connective tissues are gelatinized, and 

 the muscular flesh thus partially softened and disintegrated. On the 

 whole, the effect of cooking upon meat is to increase the consistency 

 of its albuminous ingredients, its principal benefit being the attractive 

 flavor which is developed by the aid of heat, and no doubt an increased 

 digestibility from the same cause. By either method, meat loses in 

 cooking from 25 to 30 per cent, of its weight, principally by the escape 

 of water and liquefied fat. 



Eggs. The eggs of various animals are used for food, as those of the 

 common fowl, the duck, goose, turkey, seafowl, turtles, and the roe of 

 many kinds of fish. Those of the common fowl, which are the most 

 abundantly used, may be considered as representing the general quali- 

 ties of this article of nourishment. They consist of the globular " yolk," 

 surrounded by a layer of albumen or " white." The composition of 

 these two portions is nearly the same, excepting that the yolk contains 

 a larger proportion of solids and particularly of fatty matter which gives 

 to it its yellow color and rich flavor. A comparative analysis of the 

 yolk and white is as follows : 



COMPOSITION OF THE FOWL'S EGG. 



Yolk. White. 



Albuminous matter 16.0 20.4 



Fat 30.7 



Mineral salts 1.3 1.6 



Water 52.0 78.0 



100.0 100.0 



The mineral matters consist mainly of the sodium and potassium 

 chlorides, potassium sulphate, and lime and magnesium phosphates. 

 Of the entire contents of the egg, exclusive of the shell, the yolk consti- 

 tutes one-third, and the white two-thirds. Cooking produces but little 

 effect upon eggs except to coagulate their albuminous matters, since 

 these are comparatively but little susceptible of developing any marked 

 flavor by the action of heat. 



Vegetables. Of the different vegetables used as food, some are valu- 

 able for their solid starchy and albuminous ingredients, others mainly 

 for their saccharine and watery juices. The former are nutritious in 

 the ordinary sense of the word, though much less so than bread or ani- 

 mal food ; the latter are useful for supplying certain materials contained 

 in the fresh vegetable juices which are essential to the continued main- 

 tenance of health. The most important of the first group are repre- 

 sented by the potato and the leguminous seeds. The tuber of the potato 

 abounds in starch, but is poor in other nutritive ingredients. 



