Hatat, Centrosome in Nerve Cells. 39 
(3). The sphere is nearly the same in size throughout the 
different classes of the nerve cells in the same animal and the 
size does not alter with the age of the cell. 
(4). In most cases the centrosome is composed of two 
corpuscles, but more than two rarely, and sometimes of only 
one. 
(5). The centrosome in an adult rat shows a slight ten- 
dency to degenerate when compared with that of the rat at birth. 
VI. ILLUSTRATIONS OF THE CENTROSOME IN THE NERVE CELLS OF 
THE WHITE RAT. 
The following pictures are free-hand drawings, the enlargements of the 
drawings being dissimilar. The actual size of the cells is however, given in 
the case of each figure, and by the aid of these measurements the cells can be 
compared. 
PLATE IT; 
Fig. 4. Spinal ganglion cell of an adult white rat. Cell-body, 55x39 mu; 
nucleus, 17X14 4. GILSON’s fluid. 
fig. 2. Large pyramidal cell of an adult white rat. Cell-pody, 2319 uw; 
nucleus, 13X12 /l. 
Fig. 3. Giant pyramidal cell of a young white rat. Cell body, 17x 10 ju; 
nucleus, 11X8 su. 
fig. 4. Corpus dentatum of a young white rat. Cell-body, 19x13 4h; 
nucleus, 118 sz. 
fig. 5. Purkinje cell of an adult white rat. Cell-body, 2117 4; nucleus, 
12.5X9 H. 
figs. 6-10. Purkinje cells of a young white rat. Cell-bodies, 1511 sl; 
nuclei, 9X8 4—mean diameters. 
Fig. rr. Spinal ganglion cells of an adult white rat. Cell-body, 49 44 44; 
nucleus, 15X15 4. 
From figs, 2-17. The materials were preserved with the author’s new 
mixture. 
