G. Carl Huber 55 



gular or somewhat spindle-shaped, with a varying number of processes 

 (usually not more than four or five), which may be traced for short 

 distances between the nerve fibers; such processes are, however, not 

 always made out and when present give the cell a very characteristic 

 appearance. These cells are easily recognized in longitudinal sections 

 of the spinal cord by reason of the structure of their nuclei. The cell 

 protoplasm is often clearly brought out, the cells presenting a rectangu- 

 lar or irregularly oval shape with now and then a few short processes. 

 The small, round or oval deeply-staining nuclei are often associated 

 with a small amount of protoplasm, which usually stains somewhat 

 deeply, often making it difficult to distinguish between protoplasm and 

 nucleus. 



The neuroglia fibers stain deeply blue. They vary somewhat in size, 

 but the majority are relatively fine and only here and there does one 

 find coarser fibers. The relation of the neuroglia fibers to the neu- 

 roglia cells or free nuclei is generally easily ascertained, in both cross 

 and longitudinal sections of the cord. In the majority of instances, 

 the neuroglia fibers are seen passing over or under the neuroglia cells 

 or nuclei and appear independent of them. Other fibers are seen, how- 

 ever, in close proximity to cells and are seen to lie against them. The 

 large neuroglia cells with protoplasmic branches are particularly inter- 

 esting in this connection. In such cells it is often possible to trace one 

 or several neuroglia fibers along the side of a protoplasmic branch to the 

 cell body and then either directly across the cell and away from it, or 

 along the side of some other protoplasmic branch and then away from 

 the cell. Three, four or more neuroglia fibers may thus be traced over 

 or under or along the borders of one of these branched neuroglia cells. 

 Usually also numerous small blue dots, cross sections of neuroglia fibers, 

 are seen in close proximity to such cells and now and then in the 

 peripheral portion of their protoplasm; this latter fact must be inter- 

 preted as showing that some of the neuroglia fibers pass through the 

 protoplasm of the neuroglia cells. Longitudinal sections of the cord 

 give a better idea of the course of the neuroglia fibers than can be 

 gained from cross sections. In longitudinal sections it will be seen 

 that the neuroglia fibers run parallel to the nerve fibers, at right 

 angles to them and obliquely across them. The relation of the neu- 

 roglia fibers to the deeply-staining cells above mentioned is often more 

 difficult to make out, since the cell protoplasm of such cells and the 

 neuroglia fibers now and then stain more nearly the same color than 

 is the case with other cells. In such cells, the neuroglia fibers often 

 appear as processes of the cells, especially when a cross section is studied 



