1898-99.] STRUCTURE, MICRO-CHEMISTRY AND DEVELOPMENT OF NERVE CELLS. 427 
with eosin and toluidin blue, there is in the bodies of most nerve cells 
no blue-stained substance, while the nucleus is full of blue-stained 
granules and threads (Fig. 5). On staining sections in the Ehrlich- 
Biondi mixture, one finds the cell body is red, but all the nuclear chro- 
matin is greenish, and there is no difference in the staining reactions of 
the nuclei of nerve and neuroglia cells such as is found between these 
cells in mammals. 
The reactions for iron (Fig. 7) and for phosphorus (Fig. 6) show there 
is no iron and little phosphorus in the bodies of most nerve cells. 
In a few cases a little basophile substance was observed in the cell 
body. In these the cytoplasm also contained a slight amount of 
iron and phosphorus-holding substance, but the much greater part of this 
substance, or of the substance staining with basic dyes, is in the nucleus 
A sufficient number of specimens to determine the cause of the presence 
or absence of this slight amount of basophile substance in the cytoplasm 
have not been examined, but when it is present, it is most frequently 
diffuse and not in granular form, although the latter, in rare cases, has 
been seen. 
On digestion little material is dissolved from the nucleus, but the 
oxyphile substance, which was present in traces previously, has now 
disappeared (Fig 9). Those cells which contain a little basophile sub- 
stance in the cytoplasm retain it after digestion. 
The action of alkalies on the nerve cells of these animals is similar to 
their action on the neuroglia cells of the adult, or on the nerve cells of 
embryo mammals. Thus, after six days in a solution of potassium 
hydrate (0.27) the nuclei still held a large quantity of material which 
contained iron and phosphorus, and which stained with toluidin blue, 
This same solution had removed all the basophile material from the 
cytoplasm of the nerve cells of adult mammalia in a few hours, but the 
nucleolus of the nerve cell and the neuroglia cells stained with basic 
dyes after six days, and the same was true of the embryonic nerve cells 
of mammals. The nuclei of the neuroglia cells of these Urodela, as in 
mammals, resist the action of alkalies. There is, therefore, in the 
former, no difference with respect to the action of alkalies between the 
nuclei of nerve and neuroglia cells. The slight amount of the basophile 
material present in some cells is easily and quickly altered by the 
alkali. 
For some reason, the transformation and diffusion of the chromatin 
has not proceeded, in the cells of the Urodela, past a certain stage, cor- 
