28 STRUCTURAL COMPOSITION OF HUMAN BODY. 



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 of - lymph and chyle, 

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

 a salt of iron, probably a phosphate, exists in consider- 

 able quantity in the hair, black pigment, and other 

 deeply coloured epithelial or horny substances. 



Aluminium, Manganese, and Copper. It seems most likely 

 that in the human body, copper, manganesium, and aluminium 

 are merely accidental elements, which, being taken in 

 minute quantities with the food, and not excreted at once 

 with the faeces, are absorbed and deposited in some tissue 

 or organ, of which, however, they form no necessary part. 

 In the same manner, arsenic and lead, being absorbed, may 

 be deposited in the liver and other parts. 



CHAPTEE IV. 



STRUCTURAL COMPOSITION OF THE HUMAN BODY. 



ITST the investigation of the structural composition of the 

 human body, it will be well to consider in the first place, 

 what are the simplest anatomical elements which enter into 

 its formation, and then proceed to examine those more 

 complicated tissues which are produced by their union. 



It may be premised, that in all the living parts of 

 all living things, animal and vegetable, there is in- 

 variably to be discovered, entering into the formation of 

 their anatomical elements, a greater or less amount of a 

 substance, which, in chemical composition and general 

 character, is indistinguishable from albumen. As it exists 

 in a living tissue or organ, it differs esentially from mere 



