April i r, 1890.] 



SCIENCE. 



227 



the United States National Museum at Washington, showing 

 the approximate weights of the chemical elements found in 

 the body of a man five feet eight inches high, weighing one 

 hundred and forty-eight pounds (Table I.). It is obvious 

 that the composition of the bodies of different persons will 

 vary with age, size, sex, stoutness, etc. ; so that the figutes 

 given in the following table can only be considered typical. 



Table I. — Chemical Composition of the Human Body 

 [calculated by Professor W. O. Atwater). 



We find in the above table, that, when the innumerable 

 organic and inorganic compounds of which our bodies are 

 composed are reduced lo the simple form of their chemical 

 elements, they can be divided into three groups: first, gases 

 (oxygen, hydrogen, nitrogen, chlorine, and fluorine, — five) ; 

 second, solids, non-metals (carbon, phosphorus, and sulphur, 

 — three); and, third, solids, metals (iron, calcium, magne- 

 sium, potassium, and sodium, — five). Besides these thir- 

 teen elements, minute quantities of a few others, as silicon, 

 manganese, and copper, are found in the body. 



The principal materials of which the body is composed 

 may be briefly stated as follows. The flesh (muscles) con- 



sists of water, fat, inosite, flbrine, albumen, myosin, gela- 

 tine, certain extractives, and salts of lime, magnesia, potash, 

 soda, iron, and phosphorus. Blood is in composition very sim- 

 ilar in its elements to that of flesh. Bone, of which about 30 

 per cent is mineral matter composed of salts of lime, magnesia, 

 potash, soda, and phosphorus, contains cartilage, gelatine, 

 and fat. Cartilage consists of collagen and other gelatinoids, 

 with salts of soda, potash, lime, magnesia, iron, phosphorus, 

 and sulphur. The brain, nerves, and spinal cord contain 

 substances called protagon, cerebrin, etc., consisting of nitro- 

 genized and phosphorized fats, also water, and mineral salts. 

 The liver is formed of water, fat, glycogen, and albumi- 

 noids, besides salts of potash, soda, lime, iron, and phosphorus. 

 The lungs consist of gelatinoids and albuminoids, fibrine, 

 various fatty and organic acids, cholestrin, and salts of soda 

 and iron, and water. 



Chemical Composition of Different Foods. 



It will seem strange to many that substances seemingly 

 as dissimilar as flesh and wheat should contain the same class 

 of chemical elements; yet in both we find water and mineral 

 salts, nitrogenous materials, fats, and carbohydrates, as 

 Table II. shows. 



Proteine. 



The most important class of food-material is that contain- 

 ing nitrogen, which is usually present in the form of albu- 

 minoids; i.e., organic substances very similar in chemical 

 composition to albumen or "white of egg," or in the form 

 of gelatinoids, i.e., organic substances similar to gelatine in 

 chemical composition ; and it is customary for chemists to 

 call both by the generic name of "proteine." Lean meat, 

 the curd of milk, and the gluten of wheat, consist princi- 

 pally of proteine compounds. The "extractives," as chem- 

 ists call the organic compounds, containing nitrogen, which 

 are extracted from flesh by treatment vrith water, — beef-tea, 

 extract of beef, etc., — are interesting, in that they act as 

 stimulants, like alcohol, and are not nutrients. The other 

 two organic classes of foods, which, however, do not con- 

 tain nitrogen, are the fats and the carbohydrates. 

 Fats. 



The fats contain the chemical elements, carbon, hydrogen, 

 and oxygen, and are known as the glycerides of the fatty 



Table IL— Average Chemical Composition, of Different Food-Materials. 



Food-Material. 



Ox, flesh, very fat 



" " medium fat. 



" " lean 



" fat, heart 



" lungs 



" liver 



Cow, flesh, fat 



Calf, 



lean, 

 fat. 



lean 



very fat 



meolum fat. 

 fat.. 



Hog, 



" *' lean 



Horse " 



Blood 



Salmon 



Mackerel 



Shad 



Oysters, flesh 



" liquor 



" flesh and liquor. 



Woman's milk 



Cow's " 



Goat's " 



Sheep's " 



Butter 



Oleomargarine 



Cheese, full cream 



" whole milk 



" skimmed milk . . 



In the Original SuOstance. 



in th.e Dried Substance. 



