HISTOLOGY. 



659 



tHE HUMAN Bi)DY, ITS PHYSIOLOGICAL COMPOSITION 



CHARACTER. 



The elementary substances found in the human hody are 

 oxygen, hydrogen, carbon, nitrogen, phosphorus, sulphur, 

 chlorine, fluorine, iron, manganese, titanium, and calcium. 

 Silenium is found in the hair, and fluorine in combination 



13 1* 



Fig. 300. Diagram showing various forms of development in Animal Cells. 



1, Shows a newly formed cell. 2, Subdivision of the nucleus. 3, The nucleus 

 changes its situation, and at 4, subdivides and disappears. 5, The walls of 

 the cell increase in thickness. 6, the cell becomes branched, or stellate. 7, 

 Two cells are seen to coalesce. 8, They have coalesced and run into each 

 other. 9, Again they take another form and become multilocular. 10,11,12, 

 Cells sprouting out to form membrane and vessels. 14, Development of 

 complicated cells, which, at 13, have coalesced to form tissue. 



with lime forms the enamel of the teeth. Iron is the 

 chief colouring-matter of the blood, the black pigm-ent of 

 the choroid of the eye, and the skin of the negro, 

 u u 2 



