THE CELL DOCTRINE. 91 



"which is to produce the new cell, and which almost 

 alwaj's assumes the spherical form when allowed to 

 float freely. (See Figure 10 of frontispiece.) The 

 formed material is never active, according to Beale, 

 but entirely passive in the process of cell multiplica- 

 tion. 



Nutrition of Cells. — So, too, in the nutrition of the 

 cell, the germinal matter is the sole active agent. 

 The formed material may act as a filter to the nu- 

 trient matter, but is quite passive. The pabulum, 

 which is coursing through the bloodvessels, becomes 

 converted into germinal matter, which in turn be- 

 comes formed material, aud so long as this is kept 

 up, the cell continues to grow. The course taken by 

 the pabulum, and the order of conversion, is shown 

 by the arrows, in Figure 17, of frontispiece, and will 

 be readily understood by reference to the explanation. 

 Occasionally, and especially in disease, the formed 

 material may become the pabulum for rapidly mul- 

 tiplying cells, and thus be consumed. 



Intercellular substance has already been spoken of 

 as formed material. We have it most strikingly 

 present in the white fibrous tissue, or tissue of ten- 

 dons, and in hyaline cartilage. If the former be 

 stained by carmine, and examined in thin section 

 under the microscope, it will be found composed of 

 beautiful' bands of gently waving fibrous tissue, or 

 tissue exhibiting a fibrous appearance, at varying in- 

 tervals in which are noted nuclear masses of germinal 

 matter, which have assumed the tint of carmine. Or, 

 if dilute acetic acid be added to the specimen, the 

 fibrous appearance will at once become homogeneous, 



