THE ANIMAL CELL. 53 



certain other organs, foremost of these being the liver; it will 

 therefore be more thoroughly described in connection with this 

 organ (Chapter VI). 



Another body or more correctly a group of bodies which occur 

 very widely diffused in the animal and vegetable kingdoms and 

 habitually in the cells are the cholesterines, whose best-known 

 representative is the ordinary cholesterin, specially known as the 

 chief constituent of certain biliary calculi and occurring in large 

 quantities in the brain and nerves. It is hardly to be admitted that 

 this body has any direct importance in the life and the develop- 

 ment of the cell. It is more probable, as HOPPE-SEYLER suggests, 

 that cholesterin is a splitting product appearing in the general life- 

 processes of the cells. Also according to HOPPE-SEYLER the fat, 

 which does not constantly appear in the cell, has nothing to do 

 with the general process of life. 



Mineral bodies are also never-failing constituents of the cell. 

 These minerals are potassium, sodium, calcium, magnesium, iron, 

 phosphoric acid, and chlorine. In regard to the alkalies we find in 

 general in the animal organism that the sodium combinations are 

 more abundant in the fluids, the potassium combinations occur 

 chiefly in the form-constituents and in the protoplasm. Corre- 

 sponding to this the cell contains potassium, chiefly as phosphate, 

 while the sodium and chlorine combinations occur less abundantly. 

 According to the ordinary views the potassium combinations, espe- 

 cially the potassium phosphate, are of the greatest importance for 

 the life and development of the cell, even though we ^do not know 

 the nature of the importance. At least we must not overlook the 

 fact that a part of the phosphoric acid which is obtained from the 

 cell or tissue rich in cells may originate from the nuclein and leci- 

 thin in the process of ashing. Also the iron, which often occurs in 

 the ash as ferric phosphate, seems, at least in part, to be formed 

 from the nucleo-albumin. The habitual occurrence of earthy 

 phosphates in all cells and tissues, together with the difficulty or 

 almost impossibility of separating these bodies from the protein 

 substances without decomposition, leads us to suppose that these 

 mineral bodies are indeed, though their role is still unknown, of 

 the greatest importance for the life of the cells and the chemical 

 processes which accompany their evolution. 



