1898-99.] STRUCTURE, MICRO-CHEMISTRY AND DEVELOPMENT OF NERVE CELLS. 423 
ordinary reactions in six hours, but the nucleolus of the nerve cell and 
the nuclei of the neuroglia cells manifested their ordinary reactions, 
although more diffusely, at the end of the six days. 
On digestion of material which had been fixed in alcohol there 
was no appreciable effect on the nuclein compounds until a stage of 
which Figs. 19 and 21 are representations. In the stage illustrated in 
Figure 21, which is from the cord of an embryo of 32mm., all the 
oxyphile nuclear substance digests as in the adult, but in stages before 
this one, there is always some substance which does not disappear 
on digestion. After digestion the periphery of the nucleolus always 
remains. In this respect as well as in all its other reactions it resembles 
the chromatin found in primitive nerve cells. 
In order to facilitate reference to the different stages through which 
the chromatic substance passes in getting into the cytoplasm of the 
nerve cell I shall adopt the example of His and divide the process 
(arbitrarily) into different stages. 
Stage 1. Germinating cells (Figs. 12, 13, and 14), stages 1, 2, and 3 
of His. The chromatin is confined to the nucleus and is in mitosis, 
Weak alkalies alter this substance very slowly. Digestion dissolves the 
cell body but does not alter the staining power of the chromatin. 
Stage 2. Neuroblast stage (Fig. 15), stage 5 of His. The chromatin 
is confined to the nucleus but is broken into masses. A nuclear mem- 
brane has been formed and the greater portion of the chromatin is dis- 
tributed around the membrane. Alkalies and digestive fluids have little 
or no power to alter the reactions of this substance. 
Stage 3. (Figs. 16, 17, 18, 19 and 20), stage 4 of His. Some of the 
kinetic chromatin is transformed into two other kinds, an oxyphile and 
a basophile. As the chromatin alters, the basophile part diffuses into 
the cytoplasm but the oxyphile substance remains in the nucleus. Most 
of the chromatin alters at the same rate but there may still be masses in 
the nucleus with marked affinity for basic stains. Alkalies have an 
altering action on the diffused-out chromatin in extracting the iron from 
its substance, thus changing its staining reactions. Digestive fluids 
affect the nucleus but still leave the basophile parts behind. 
Stage 4. (Fig. 21). The transformation of the kinetic chromatin into 
the oxyphile and basophile kinds is now completed and the diffused 
basophile part fills the whole cell body. Alkalies alter the chromatin, 
especially the diffused part. Digestion dissolves the oxyphile substance 
