1 8 CHEMICAL COMPOSITION OF HUMAN BODY. 



flesh always contains a much larger proportion of potash- 

 salts than of soda-salts; while in the blood and other 

 fluids, except the milk, the latter salts always preponderate 

 over the former; so that, for example, for every 100 parts 

 of soda-salts in the blood of the chicken, ox, and horse, 

 there are only 40*8, 5*9, and 9-5 parts of potash-salts ; but 

 for every IOO parts of soda-salts in their muscles, there 

 are 381, 279, and 285 parts of potash-salts. 



The salts of calcium are by far the most abundant of the 

 earthy salts found in the human body. They exist in the 

 lymph, chyle, and blood, in combination with phosphoric 

 acid, the phosphate of calcium being probably held in solu- 

 tion by the presence of phosphate of sodium. Perhaps no 

 tissue is wholly void of phosphate of calcium; but its 

 especial seats are the bones and teeth, in which, together 

 with carbonate and fluoride of calcium, it is deposited 

 in minute granules, in a peculiar compound, named 

 bone-earth, containing 51*55 parts of lime, and 48*45 of 

 phosphoric acid. Phosphate of calcium, probably the 

 neutral phosphate, is also found in the saliva, milk, bile, 

 and most other secretions, and acid phosphate in the urine, 

 and, according to Blondlot, in the gastric fluid. 



Magnesium appears to be always associated with calcium, 

 but its proportion is much smaller, except in the juice 

 expressed from muscles, in the ashes of which magnesia 

 preponderates over lime. 



The especial place of iron is in the haemo-globin, the 

 colouring-matter of the blood, of which a further account 

 will be given with the chemistry of the blood. Peroxyde 

 of iron is found, in very small quantities, in the ashes of 

 bones, muscles, and many tissues, and in lymph and chyle, 

 albumen of serum, fibrin, bile, and other fluids; and a 

 salt of iron, probably a phosphate, exists in considerable 

 quantity in the hair, black pigment, and other deeply 

 coloured epithelial or horny substances. 



Aluminium, Manganese, Copper, and Lead. It seems most 



