THE CELL AND PROTOPLASM. 



93 



It appears in great variety in different cells, but 

 it always has remarkable physiological properties, 

 as will be noticed presently. All things consid- 

 ered, this chromatin is probably the most remark- 

 able body connected with organic life. 



The nucleii of different animals and plants all 

 show essentially the characteristics just described. 

 They all contain a liquid, a linin network, and a 

 chromatin thread or network, but they differ most 

 remarkably in details, so that the variety among 



FIG. 26. Different forms of nucleii. 



the nucleii is almost endless (Fig. 26). They differ 

 first in their size relative to the size of the cell ; 

 sometimes especially in young cells the nucleus 

 being very large, while in other cases the nucleus 

 is very small and the protoplasmic contents of the 

 cell very large; finally, in cells which have lost 

 their activity the nucleus may almost or entirely 

 disappear. They differ, secondly, in shape. The 

 typical form appears to be spherical or nearly so ; 



