Structure and Polarity of Electric Motor Nerve-Cell in Torpedoes. 229 
the largest of them are far smaller than the smallest karyosomes. Like 
the karyosomes they take basic dyes and in the best sublimate fixations 
they also stain black with iron hematoxylin. These perichromosomes 
were not differentiated by Magini from the general mass of perichro- 
matin of the spherule. 
The perichromosomes are much smaller and more numerous than 
any of the karyosomes; it may be said that they form a group of gran- 
ules grading down from the less numerous larger ones to finer and 
more numerous, until the successive sizes become so small that they 
can no longer be seen. Hence, it is possible that the visible perichromo- 
somes are not different in substance from the mass of perichromatin 
in which they lie. They appear in most cases to stain in much the 
same way as the cloud of finer perichromatin in general, and this 
perichromatin usually stains differently from the karyosome in its 
midst. The larger perichromosomes are faintly visible in the fresh 
state. They seem quite a different substance than the karyosomes. 
Taken as a mass, each karyosome, together with its spherical sur- 
rounding framework of linin in which are dissolved or borne as fine 
granules the perichromatin and perichromosomes, forms a unit which 
is, as has been said, of about the size of a full-sized single plasmosome. 
It will be convenient and perhaps permissible to call these complete 
units the “chromatin bodies.’”’ It is possible that they are the same as 
the chromosomes of dividing cells. 
It may thus be seen that in the adult electric motor nerve-cells of the 
torpedoes in general there are at least six apparently separate materials 
which are not dissolved by the usual fixatives by subsequent handling 
with reagents, and which can be recognized and compared by their 
size, Shape and staining capacity as well as, in some cases, by their 
specific gravity and their refractive index. 
I regard these substances as organic compounds that take part in 
the life and activity of the nucleus and therefore of the cell, but some 
of which, at the time the cell is fixed in a more or less solid state, are 
possibly in a state of storage or temporary disuse. The reason for 
their solid form is a question of segregation of the particular material 
involved. This does not imply that the material in question is not 
active, for it probably is, but it does seem that it is necessary, for 
physiological-chemical purposes, that it be more or less concentrated 
at some particular point. Nor is its solidity an absolute one, but 
consists of varying degrees of gelatinization or even of strong solution, 
which are usually much intensified by the fixation, ete. Many other 
constituent substances of the nucleus must be in the form of solutions 
that are not precipitated by our fixatives and are consequently not 
ordinarily studied. Some of the latter substances are sometimes pre- 
cipitated and preserved for study, and sometimes they remain in solu- 
ble form or are even converted from solid and gel forms to a solution 
