292 CHI PING 
At birth or during the first days of life there are found among 
the young cells a few advanced cells which appear conspicuously 
different from the rest. In these advanced cells the cytoplasm 
may be already differentiated, even at birth. The stainable 
Nissl granules, which are of course much finer than those found 
at later ages, are evenly but distinctly distributed through the 
entire contents of the cell. Among these granules some clear 
spaces appear which seem to indicate the differentiation of the 
homogeneous cytoplasmic mass, and this change in the advanced 
cells must have commenced during fetal life. 
When the young cells begin to develop, there is the same dif- 
ferentiation of the cytoplasmic mass, and the stainable bodies 
arrange themselves in the same way as those seen in the advanced 
cells. Hereafter more differentaition will be found in them and 
they grow to resemble the advanced cells in appearance. 
Taking this as the starting-point in the morphological develop- 
ment, we see among the comparatively large cells in the ganglion 
four types which probably appear one after the other as here 
given in the course of growth. 
Type 1. The advanced cells and the cells which are trans- 
forming into advanced cells, as described above, belong to this 
type. ‘There is a beginning of aggregation of the Nissl granules 
and a growth of the unstainable ground-substance in the cells. 
This type is common during the first twenty days of postnatal 
life (fig. 2). . 
Type 2. The Nissl bodies are larger than in type 1 and 
ageregated at the periphery of the cells, forming a ring within 
which is a comparatively clear portion of the ground-substance 
surrounding the nucleus. The Nissl bodies stain much darker 
than in type 1. The nuclear membrane, the nucleoli, and the 
reticular structure in the nucleus are distinctly visible. There 
are frequently two or more nucleoli in one nucleus. This type 
is common in the period between twenty and sixty days (fig. 3), 
but may also be found at birth (fig. 1). 
Type 3. Instead of being distributed at the periphery, the 
Nissl bodies are aggregated around the nucleus, leaving a rather 
clear space at the periphery of the cell. In some of the cells they 
