102 



NORMAL HISTOLOGY. 



The glia-cells possess delicate processes, which lie in the cement- 

 or ground-substance and form a felt-like mass of interlacing fila- 

 ments, but do not unite with each other. Two types of cell may be 

 distinguished, but they are not sharply defined, because intermediate 

 forms are met with. In the first type the cells have relatively large 



FIG. 89. 

 f 



FIG. 90. 



Glia-cells from the human spinal cord. (Retzius.) 

 Fig. 89. Cells from the substantia gelatinosa Rolandi of the posterior horn. The cell to the 



right has a long process beset with fine, bluish branches. 

 Fig. 90. Four cells from the gray matter. 

 Figs. 87-90 are taken from specimens stained by Golgi's method, which fails to reveal the 



internal structure of the cells, but is extremely well adapted to show the shapes of the 



cells and their extension into fine processes. 



bodies, beset with a multitude of comparatively short, very fine, and 

 frequently branching processes (Figs. 89 and 90). This type is most 

 frequently met with in the gray matter. The second type of glia- 

 cell is represented by cells with smaller bodies and longer and some- 

 what coarser processes that branch much less freely (Figs. 87 and 88). 

 They also often possess one particularly large and prominent proc- 

 ess of greater length than the others. The small bodies of these 

 cells serve to distinguish them from nerve-cells, with which they 

 might otherwise be easily confounded. This type predominates in 

 the white matter. 



Aside from the processes of the glia-cells already mentioned, the 



