128 HANDBOOK OF PHYSIOLOGY. 



Iron. The especial place of iron is in haemoglobin, the coloring-mat- 

 ter of the blood, of which a full account will be given with the chemistry 

 of the blood. Peroxide of iron is found, in very small quantities, in the 

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

 albumin of serum, fibrin, bile, milk and other fluids; and a salt of iron, 

 probably a phosphate, exists in the hair, black pigment, and other deeply 

 colored epithelial or horny substances. 



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

 in the human body, copper, manganesium, aluminium, and lead are 

 merely accidental elements, which, being taken in minute quantities with 

 the food, and not excreted at once with the faeces, are absorbed and de- 

 posited in some tissue or organ, of which, however, they form no neces- 

 sary part. In the same manner, arsenic, being absorbed, may be depos- 

 ited in the liver and other parts. 



