OF FOOD. 113 



COMPOSITION OP EGGS. 

 White of Egg. 



Water .... 80.00 



Albumen and mucus . 15.28 ..... 



Yellow oil 



Salts .... 4.72 



100.00 1UO.OO 



In ordinary flesh or butcher's meat, we have the albuminoid 

 matter of the muscular fibre and the fat of the adipose tissue. 



COMPOSITION OF ORDINARY BOTCHER'S MEAT. 



I Water . . . .63.418 

 Meat devoid of fat . 85.7 \ Solid Inatter . . . 22.282 



Fat, cellular tissue, &c 14.300 



100.000 



From what has been said above, it will easily be seen that the 

 nutritious character of any substance, or its value as an article of 

 food, does not depend simply upon its containing either one of the 

 alimentary substances mentioned above in large quantity ; but upon 

 its containing them mingled together in such proportion as is 

 requisite for the healthy nutrition of the body. What these pro- 

 portions are cannot be determined from simple chemical analysis, 

 nor from any other data than those derived from direct observation 

 and experiment. 



The total quantity of food required by man has been variously 

 estimated. It will necessarily vary, indeed, not only with the con- 

 stitution and habits of the individual, but also with the quality of 

 the food employed ; since some articles, such as corn and meat, con- 

 tain very much more alimentary material in the same bulk than 

 fresh fruits or vegetables. Any estimate, therefore, of the total 

 quantity should state also the kind of food used ; otherwise it will 

 be altogether without value. From experiments performed while 

 living on an exclusive diet of bread, fresh meat, and butter, with 

 coffee and water for drink, we have found that the entire quantity 

 of food required during twenty-four hours by a man in full health, 

 and taking free exercise in the open air, is as follows : 



Meat . . . . .16 ounces or 1.00 Ib. Avoirdupois. 



Bread 19 " " 1.19 " 



Butter or fat . . . . 3.} " " 0.22 " " 



Water 52 fluid oz. " 3.3^ - " 



That is to say, rather less than two and a half pounds of solid food, 

 and rather over three pints of liquid food. 



