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CHAPTER III. 



CHEMICAL COMPOSITION OF THE HUMAN BODY. 



THE following Elementary Substances may be obtained by 

 chemical analysis from the human body : Oxygen, Hydro- 

 gen, Nitrogen, Carbon, Sulphur, Phosphorus, Silicon, 

 Chlorine, Fluorine, Potassium, Sodium, Calcium, Magne- 

 sium, Iron, and probably, or sometimes, Manganesium, 

 Aluminium, and Copper. 



Thus, of the sixty-three or more elements of which all 

 known matter is composed, more than one fourth exist 

 in the human body. A few others have been detected in 

 the bodies of other animals ; but no element has yet been 

 found in any living body which does not also exist in 

 inorganic matter, and for the simple reason that all the 

 structures of a living being are composed of elements 

 which have been withdrawn, directly or indirectly, from 

 the inorganic world, again to return, after a certain time, 

 to their original condition. It is, therefore, in the arrange- 

 ment of these elements, not in their nature, that we must 

 seek for those distinctions which exist between what is 

 called organic and inorganic matter. 



The term organic has long ceased to imply a substance 

 that is formed only by organized living tissues, and 

 now signifies only matter with a certain degree of com- 

 plexity of composition. The term, indeed, for want of a 

 better, is still retained, although its original meaning has 

 been lost. But distinctions founded upon the supposed 

 fact that certain substances can be formed by the agency 

 of life only, are fast disappearing, as the chemist, year by 

 year, adds to the number of his conquests over inorganic 

 matter, and moulds it to organic shape. 



