78 THE CELL DOCTRINE. 



whole of the germinal matter. There maybe other 

 older germinal matter beyond the nucleus, on its 

 way to conversion into formed material, but still 

 germinal matter, which assumes a tint with carmine, 

 but not so deep as the nucleus. Thus, the entire 

 mass of the pus corpuscle (Plate, Fig. 10), except its 

 extreme periphery, is germinal matter, yet there is 

 within this another younger portion of germinal 

 matter, taking a deeper tint with carmine, but which 

 alone of the elements of this cell, we are in the habit 

 of calling " nucleus." The " nucleus" then, is noth- 

 ing but a new centre of germinal matter, and the 

 "nucleolus" is a younger centre. And there may 

 even be within this, a still younger portion of living 

 matter, taking even a deeper stain, which might be 

 called a "nucleoleolus." By this staining process may 

 we distinguish the nucleolus from a minute oil-drop 

 often mistaken for it, and which will not assume any 

 tint. 



On the other hand, germinal matter in a compar- 

 atively quiescent state is often quite destitute of 

 nuclei. But let the mass be freely supplied with 

 nutrient matter and nuclei and nucleoli rapidly 

 make their appearance. 



So with regard to the "cell contents" over and 

 above the nucleus, although they may all be germinal 

 matter, yet this is not necessarily the case. Thus in 

 the white blood corpuscle and mucous corpuscles, 

 what Yirchow would consider cell contents is all ger- 

 minal matter; but the superficial epithelial cell lining 

 the interior of the mouth has its nucleus alone com- 

 posed of germinal matter, and much that has been de- 



