1898-99.] STRUCTURE, MICRO-CHEMISTRY AND DEVELOPMENT OF NERVE CELLS. 435 
described before, nor have I noticed any difference in the staining power 
of the nuclear membrane next the micro-centre,although I have observed 
many of the different conditions of the cell with respect to the distribu- 
tion of the granules described by Holmgren. Thus, after the chromatin 
has once diffused from the nucleus, nothing occurs, in my opinion, to 
indicate the renewal of the granular substance from that organ. I do 
not deny that such renewal may take place, but if it does, it is in solu- 
tion and not in formed masses. Further investigation, however, is 
necessary to decide this point. 
Concerning the reason for the diffusion of the chromatin from the 
nucleus, it may be to aid physiological action, for it is a general 
rule, which no physiologist would now deny, that an_ iron-holding 
nucleo-proteid is necessary for the cell to carry on its normal function. 
These compounds are generally confined to the nucleus, but they occur 
in the cell body of all gland cells. It seems to me that it would aid 
physiological action in having these nuclein compounds in direct contact 
with the cytoplasm of the nerve cells, for in this case the cytoplasmic 
action would not be delayed by immediate participation of the nucleus. 
Thus cytoplasmic impulses may pass from one process of the cell into 
another without going through the nucleus, which could not happen if 
the chromatin had remained in the latter. 
V.—CONCLUSIONS. 
The Nissl granules are of a nucleo-proteid nature, since they contain 
“masked ” iron and organic phosphorus, and are derived from the nu- 
clear chromatin of the germinating cells. Pepsin and hydrochloric acid 
do not dissolve them, nor are they dissolved by alkalies or acids which, 
‘however, liberate the iron, and in consequence of this their staining re- 
actions are altered. Digestion with pepsin and hydrochloric acid does 
not affect the occurrence of iron and phosphorus in the granules. 
The nucleolus consists of an oxyphile centre with a_basophile 
covering. The basophile covering seems to correspond to the original 
kinetic chromatin otf the germinating cell. It contains iron and phos- 
phorus, and alkalies extract the iron very much more slowly from it 
than they do from the Nissl granules. 
The oxyphile nuclear substance is also a nuclein compound since it 
contains iron and phosphorus. It is readily dissolved in pepsin and 
