Structure and Polarity of Electric Motor Nerve-Cell in Torpedoes. 223 
living cell it can in no way be considered as the network or thread-like 
structure that we find supporting the nucleolar bodies after fixation. 
I think this is easily proved by the following facts: In torpedoes Nos. 
20 and 4 the peripheral cells in control specimens show a centrally 
placed or ventrally oriented plasmosome and the accessory nucleoli 
distributed throughout the cell. It is evident, upon inspection of the 
drawing and preparations, that in that condition, and given the pres- 
ence of such a fine-meshed network, the plasmosome and accessory 
nucleoli could not be moved without breaking all the meshes and 
threads through which they had to pass. And yet in figure 23, plate 5, 
from gravity experiment on torpedo No. 4, all these bodies are shown 
down on one part of the nuclear membrane, while the entire remainder 
of the nucleus is occupied by the well-fixed, fine-meshed alveolar 
reticulum. It must be true that the reticulation of the achromatic 
material is a result of fixation and that, while living, the nucleolar 
bodies can move or be moved through it without injuring its structure. 
On the other hand, too, in cells subjected to a stronger current of elec- 
tricity (over 0.25 ampere) the various substances that are moved to the 
anode leave a thread-like reticulum that may be fairly considered to 
be a part, probably in some slightly changed condition, of the original 
structure of the nucleus. 
Of course it would be possible to have a reticulum, or better an alveo- 
lum, through which the plasmosome might move as a wet marble could 
move through soapsuds or foam. But in this case the alveolar struc- 
ture would undoubtedly show in life, which is not the case in this nerve- 
cell. Such a condition has been suggested by Murlin (27). 
Further, it would be hard to determine how far and to what degree 
this material enters mechanically into the other structures of the 
nucleus. There is reason to believe that it is denser and firmer where 
it holds together the cloud of perichromatin around the chromatin 
particles, for under several circumstances this gathering of material 
moves as a unit and independently of the other similar clouds and other 
structures of the nucleus. Here it appears to have a radial arrangement. 
The differences in the reticulum as found in different parts of the 
same preparation are in themselves of great interest. In figures 22 
and 23, plate 5, are drawn two cells, one from a Bouin fixation and the 
other from a Flemming fixation, showing how the appearance of this 
achromatic substance differs according to the distance the fixative has 
had to penetrate in order to reach it. This difference also comes out 
in figures from different preparations, and where one has studied many 
preparations he can at once say about how far from the surface the 
fixative had to penetrate to get to each cell. 
A proper fixation of the nucleus of these nerve-cells is a fairly difficult 
matter and many papers on the subject (otherwise excellent) show 
figures that indicate much deficiency in this respect. And this is aside 
