Structure and Polarity of Electric Motor Nerve-Cell in Torpedoes. 227 
call the karyosomes or chromatin nucleoli. These bodies have been 
mentioned by Garten (17 B) and others, and have been more carefully 
and particularly described by Magini in connection with a new sub- 
stance which he calls perichromatin, in a paper published by him at 
Montepulciano in 1901 (24d). My results do not in any way conflict 
with the morphological facts brought out in this excellent paper, but 
I believe that in Magini’s work and in mine the chemistry of several 
of the bodies described is not sufficiently understood to designate any 
one of the three of them as the same substance as the chromatin which 
goes into the chromosomes of embryonic tissue cells that are dividing 
by mitosis. This chromatin is surely to be found among these bodies 
and my separation of them will be a little more close than his was, but 
histogenetic, experimental physiologic, and chemical work will be nec- 
essary for a sufficient understanding of the subject. Only in failing to 
distinguish chemically (by color) between his “‘filimento nucleinico a 
gomitolo” or ‘‘rete cromatica”’ or ‘‘granuli cromatici” and his masses 
of perichromatin, do I find myself differing, and I still hope to find 
some true or basichromatin disposed in this way with other staining 
methods. 
These chromatin nucleoli are rather larger and more abundant than 
Magini states in his paper. The largest one measured in my prepara- 
tions was fully 24 microns in diameter and many could be found that 
measured 11 to 14 microns. Many also are found below 1 micron in 
size, although these very small ones do not seem to grade down to an 
excessively small granule. 
In the fresh state the chromatin nucleoli are visible and appear to 
possess a fairly high index of refraction, although not quite so high as 
that of the plasmosome. They are colorless and motionless and appear 
to be quite equally distributed through the nucleus. The larger ones 
are farther apart than the smaller. Some are placed directly against 
the nuclear wall and others at various points in the nuclear space. 
One of them is sometimes found against the side of the plasmosome. | 
In a considerable number of cases these bodies are grouped together; 
that is, instead of one being found at a single central point, two or more 
will appear, closely placed and apparently acting as a unit in the 
arrangement that has been mentioned. When so grouped, the super- 
numerary granules are usually very small, although sometimes two 
large ones will be found acting together. 
These spherules or chromatin nucleoli are homogeneous and are 
about the most easily stained bodies in the nucleus. Their staining 
powers differentiate them at once from any other nuclear content. 
Particularly good to show the chemical difference in staining are some 
of the bulk stains, as a double staining with paracarmine and hemalum 
or borax-carmine and hemalum. In either of these two, with strong 
decolorization, the chromatin nucleoli take a deep, bright, transparent 
