CHEMICAL COMPOSITION OF THE HUMAN BODY. 11 



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

 be extracted without losing their distinctive properties. 



There are about one h-undred proximate principles, which are divided 

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

 genized, and principles of waste. 



I. INORGANIC PROXIMATE PRINCIPLES. 



SUBSTANCE. WHERE FOUND. 



Oxygen, ......... Lungs and blood. 



Hydrogen, ........ Stomach and intestines. 



Nitrogen, ...... . . Blood and intestines. 



Carbonic anhydride, .... Expired air of lungs. 



Water, .......... Found in all solids and fluids. 



Sodium chloride, ...... In all fluids and solids except enamel. 



Potassium chloride, ..... In muscles, liver, saliva, gastric juice, etc. 



Ammonium chloride, .... Gastric juice, saliva, tears, urine. 



Calcium chloride, ..... Bones, teeth, urine. 



Calcium carbonate, ..... Bones, teeth, cartilage, internal ear, blood. 



Calcium phosphate, "] 



SllhVph^' [ I-l, fluids and solids of the body. 



Potassium phosphate, J 



Sodium sulphate, | TT . , M1 ,., , .... 



Potassium sulphate, } ' ' Umversal exCe P l milk blle and S astnC J U1Ce ' 



Sodium carbonate, ") , , , , , 



Potassium carbonate, } ' Bones, blood, lymph, urine, etc. 



Magnesium carbonate, . . . Blood and sebaceous matter. 



Oxygen is one of the constituent elements of all the fluids and solids of 

 the body. It is found in a free state in the respiratory passages and intesti- 

 nal tract ; it is held in solution in the lymph and plasma and forms a loose 

 combination with the haemoglobin of the blood corpuscles. The function 

 of the oxygen in the body appears to be the oxidation of albuminous, ole- 

 aginous and saccharine compounds to their ultimate forms, urea, carbonic 

 acid, water, etc. As to whether this is brought about by direct oxidation 

 or by a fermentative process is yet unknown. .As oxygen only enters into 

 combination under a high temperature, it is assumed that it exists in the 

 body under the form of ozone, O 3 , which possesses remarkably active oxid- 

 izing powers. The seat of oxidation is at present located in the tissues, as 

 the presence of ozone in the blood has not been positively demonstrated. 



Hydrogen is also a constituent element of almost all the compounds of 

 the body; it exists in a free state in the intestinal tract, where it is produced 



