NUTRITIVE POWER OF DIFFERENT KINDS OF FOOD. 



487 



the maintenance and reparation of the body.* Those which are poorest in 

 nitrogen, are richest in Carbon and Hydrogen ; and are, therefore, the best 

 adapted to serve as the pabulum for the heat-sustaining process. It is to be 

 borne in mind, however, that no table of this kind, founded simply upon the 

 Chemical composition of the various substances, can indicate their respective 

 fitness as articles of diet; since this depends also upon the facility with which 

 they are reduced by the digestive process, and afterwards assimilated. Thus 

 an aliment, abounding in nutritive matter, may be inferior to one which really 

 contains a much smaller proportion, if only a part in the first case, and the 

 whole in the second, be readily taken up by the system. In the following 

 table, Human Milk is taken as the standard ; and the quantity of Nitrogen it 

 contains is expressed by 100. But it must be borne in mind that this sub- 

 stance is intended for the nourishment of a being that passes nearly the whole 

 of its time in a quiescent state ; and must not be supposed to be adapted for 

 the sole maintenance of the Human body in a state of activity. In fact, it is 

 inferior in its proportion of Caseine (the substance of which alone the azote 

 forms a part) to the milk of most, if not all, other Mammalia ; their young 

 bringing their animal functions into exercise at a much earlier period than the 

 Human infant. 



Vegetable. 



Rice 

 Potatoes 

 Turnips 

 Rye . 

 Maize . 

 Barley 



Human milk 



Cow's milk . 



Oyster 



Yolk of eggs . 



Cheese 



Eel, raw 



. boiled 



Liver of crab 

 Mussel, raw 



boiled 



Ox liver, raw 

 Pork-ham, raw 

 boiled 



Jlnimal. 



. 100 Salmon, raw . . 776 



. . 237 boiled . . 610 



. 305 Liver of Pigeon . . 742 



. . 305 Portable soup . . 764 



331-447 White of Egg . .845 



. . 434 Crab, boiled . . . 859 



. 428 Skate, raw . . 859 



. . 471 boiled . . . 956 



. 528 Herring, raw . .910 



. . 660 boiled . . 808 



. 570 milt of . . 924 



. . 539 Haddock, raw . . 920 



. 807 boiled .816 



Peas . . . . 239 



Agaricus russula . 264 



Lentils . . .276 



Haricot beans . .283 



Agaricus deiiciosus _ 289 



Beans . 320 



Flounder, raw . . 898 



.boiled . . 954 



Pigeon, raw . .756 



boiled . . 827 



Lamb, raw . .833 



Mutton, raw . . . 773 



toiled . . 852 



Veal, raw . . .873 



boiled . .911 



Beef, raw . . . 880 



boiled . . 942 



Ox lung . 931 



648. Besides these substances, there are certain Mineral ingredients, which 

 may be said to constitute part of the food of Animals ; being necessary to their 

 support, in the same manner as other mineral substances are necessary to the 

 support of Plants. Of this kind are common salt, and also phosphorus, sul- 

 phur, and lime, either in combination or separate. The uses of Salt are very 

 numerous and important. It consists of two substances of opposite qualities, 

 muriatic acid and soda ; and the former is the essential ingredient in the gastric 

 juice ; whilst the latter performs a very important part in the production of 

 bile. Phosphorus is chiefly required to be united with fatty matter, to serve 

 as the material of the nervous tissue; and to be combined with oxygen and 

 lime, to form the bone-earth, by which the bone is consolidated. Sulphur 

 exists in small quantities in several animal tissues ; but its part is by no 

 means so important, as that performed by phosphorus. Lime is required for 

 the consolidation of the bones ; and for the production of the shells and other 



* ^'chlossberger and Kemp, in Philosophical Magazine. Nov. 1S45. 



