10 HUMAN PHYSIOLOGY. 



CHEMICAL COMPOSITION OF THE HUMAN 

 BODY. 



By chemical analysis the solids and fluids of the body can be first 

 reduced to a number of compound substances which are termed proximate 

 principles : these again can be resolved by an ultimate analysis into fifteen 

 chemical elements. The different chemical elements thus obtained, and 

 the proportions in which they exist, are shown in the following table : 



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 { O. H. C. and N. found in most of the fluids 



Carbon ... 13-50 j and all tissues except fat. 



Sulphur . . . .147 ... In fibrin, casein, albumin, gelatin; as potas- 

 sium sulpho-cyanide in saliva; as alkaline 

 sulphate in urine and sweat. 



Phosphorus . 1.15 ... In fibrin and albumin; 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 . .001 . . . 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 gj per cent, of the 

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

 C. H. N. are distinguised 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 remarkable 

 display of chemical activity. 



Chemical elements, with the exception of the gases, O. H. and N., 

 do not exist alone in the body, but are combined in characteristic propor- 

 tions to form compounds, the proxi mate princ {files, the ultimate compounds 

 to which the fluids and solids can be reduced. 



