846 
most distinctly in the inner layer (Fig. 3). In the anterior and 
posterior cortical layers we observe fine-granular, black precipitates, 
above all round the nuclei. In the nuclei themselves there is no 
reaction. Indeed, Macarrum could never observe a potassium-precipitate 
in a nucleus. This justifies the assumption that the nucleus is potas- 
sium-free, since so-called masked potassium-compounds (such as iron 
in haemoglobin) are unknown. 
Cell-boundaries between the various nuclei I did not detect, con- 
sequently I would rather describe the anterior and posterior 
cortical layer as a syncytium. It is very striking that there is a 
considerable accumulation of black grains in that portion of the 
anterior syncytium which leans on the inner-layer of the platelet. 
A regular granular layer exists on the boundary between the 
anterior syncytium and the inner layer. On the boundary between 
the inner layer and posterior syneytium my preparations do not 
reveal that accumulation of potassium-compounds. Although in some 
parts of the anterior syncytium also rods could be distinguished, 
they did not show any black coloration. The inner layer of the 
electric platelet is highly potassium-rich and it is remarkable 
that here also dark and light stripes occur, just as in voluntary 
muscular tissue. The dark stripes are diffusely black; 1 did not see 
any grains. — In pieces of voluntary muscuiar tissue taken from 
the tail of the ray, which were also treated with the potassium- 
reagent, the anisotropous discs were also diffusely black and the 
isotropous layers completely colourless. Now, because the inner layer 
of the platelet has arisen from the fibrillary part of a voluntary 
muscular fibre, we can hardly be mistaken in conceiving the alter- 
nation of dark and light stripes in the inner layer of the electric 
platelet as a remainder of the alternation of anisotropous, potassium- 
bearing and isotropous, potassiumfree discs of the muscular fibre. 
In the jelly between the platelets 1 found only potassium deposits 
in the protoplasm of the starshaped connective-tissue cells. They, 
however, are poor in potassium and so the whole quantity of 
potassium-compounds in the jelly is very small; anyhow, strikingly 
small compared with the potassium-rich electric platelet. The same 
pictures recurring in various preparations as described above, I may 
be justified in considering the above-mentioned distribution of the 
potassium-compounds to be not a casual, but a typical phenomenon. 
According to MacaLLuM the forms under which potassium occurs 
in the tissues are the following: 
1st. as a local precipitate ; 
2.4. as a series of local sharply outlined deposits; 
