10 HUMAN PHYSIOLOGY. 



CHEMICAL COMPOSITION OF THE HUMAN 

 BODY. 



Of the Sixty-four Chemical Elements, about sixteen enter into the 

 composition of the body, in the following proportions : 



Oxygen 72.00 "] O. H. and C. are found in all the tissues and 



Hydrogen 9.10 fluids of the body, without exception. 



Nitrogen 2.50 f O. H. C. and N. found in most of the fluids 



Carbon I 3-5 J and all tissues except fat. 



Sulphur 147 In fibrin, casein, albumen, gelatin; as potas- 

 sium- sulpho- cyanide in saliva; as alkaline 

 sulphate in urine and sweat. 



Phosphorus... 1.15 In fibrin and albumen ; in brain; as tri -sodium 



phosphate in blood and saliva, etc. 



Calcium 1.30 As calcium phosphate in lymph, chyle, blood, 



saliva, bones and teeth. 



Sodium 10 As sodium chloride in all fluids and solids of 



the body, except enamel; as sodium sulphate 

 and phosphate in blood and muscles. 



Potassium, 026 As potassium chloride in muscles; generally 



found with sodium as sulphates and phos- 

 phates. 



Magnesium ooi Generally in association with calcium, as phos- 

 phate, in bones. 



Chlorine 085 In combination with sodium, potassium and 



other bases, in all the fluids and solids. 



fluorine 08 As calcium fluoride in bones, teeth and urine. 



Iron 01 In blood globules ; as peroxide in muscles. 



Silicon a trace In blood, bones and hair. 



Manganesium a trace Probably in hair, bones and nails. 



Of the four chief elements which together make up 97 per cent, of the 

 body, O. H. N. are eminently mobile, elastic, and possess great atomic heat. 

 C. H. N. are distinguished for the narrow range and feebleness of their 

 affinities and chemical inertia. C. has the greatest atomic cohesion. O. 

 is noted for the number and intensity of its combinations, and its remark- 

 able display of chemical activity. 



Chemical elements do not exist alone in the body, but are combined 

 in characteristic proportions to form compounds, the proximate principles, 

 which are the ultimate compounds to which the fluids and solids can be 

 reduced. 



Proximate Principles exist in the body under their own form, and can 

 be extracted without losing their distinctive properties. 



There are about one hundred proximate principles, which are divided 

 into four classes, viz. : inorganic, organic non-nitrogenized, organic nitro- 

 genized, and principles of waste. 



