296 CHI PING 
Incidentally, pigmented cells have been noted in the superior 
sympathetic ganglion of the albino rat. The cells of compara- 
tively young animals, from birth to eighty days, are entirely 
free from pigment. At the beginning of puberty we occasionally 
find pigment in one or two cells in an entire ganglion. The 
number of the pigmented cells tends to increase as age advances, 
as recorded in table 5. Some of the cells are only partly pig- 
mented; a few are completely covered with these granules, the 
nucleus remaining unaffected, while others are totally pigmented, 
including the nucleus. The pigments appear yellow brown, or, 
black in color, but whether this is merely a result of their relative 
abundance or whether there are several sorts of pigment has not 
been determined. The whole question of pigment in the Albino 
nervous system seems worthy of a special investigation. 
INCREASE IN THE NUMBER OF THE LARGE CELLS 
The increase in the number of the large cells in the ganglion 
during the first twenty days is an important event. This is 
chiefly due to the rapid increase in diameter of the young cells 
after ten or fifteen days of age. The large cells measure 19 to 
25 uw in diameter, and are loosely scattered and intermingled 
with small cells, as seen in each section. Disregarding their 
finer differences, such a group of cells consists of three kinds: 
1. The advanced cells. During embryonic development it is 
known that the sympathetic trunks are formed through the 
migration of some cells which pass from the spinal cord along the 
paths of the communicating rami (Kuntz, 710). The advanced 
cells in the superior cervical ganglion are the forerunners of the 
neurones which come to this locality in “‘skirmish order—much 
in advance of the others”’ and ‘‘they represent but a fraction of 
the final number of large cells’? (Donaldson, 717). The number 
of these cells during the first twenty days varies from one to 
eight in the entire ganglion. 
2. The moderately large cells. These cells constitute an 
intermediate group between the advanced cells and the small 
cells in the same ganglion during the first ten days of age. They 
are not different from other younger cells in general structure and 
