— lOO — 
the case, as will also be subsequently referred to. In some parts of 
the gangUa, where small ganglion cells are situated closely together, 
the neuroglia-membranes form cavities in a similar way as the 
waxen-walls in a honeycomb, and one ganglion cell is situated in 
each cavity (vide fig. 40). 
The membranes also extend into, and envelope, the processes 
of the ganglion cells (vide fig. 26). Round the processes of a great 
many cells, sheaths of a quite peculiar structure occur, these sheaths 
will be mentioned in the description of the processes. 
The protoplasm of the ganglion cells of the lobster has 
been described in different ways by the many authors who have 
treated the subject. In one of the later and more important me- 
moirs on this subject, viz. that by FREUD (1882), it is, as we have 
seen (p, 34), described as consisting of two substances, a. reticulated 
substance, and a hyaUne viscous substance. 
Freud has specially examined ganglion cells in the fresh state, 
I have also examined them in the fresh state, but could not arrive 
at a lucid conclusion as to the structure of their protoplasm, neither 
could cells isolated by maceration afford much better information 
in this respect. 
I saw a kind of reticulation; as described by Freud. This re- 
ticular appearance was especially distinct in macerated preparations 
(cmfr. ng. 23) the meshes having a circular shape (they have be- 
come too distinct in fig. 23; the illustration not being a successfull 
one); I could, however, not convince myself whether this appearance 
was really produced by a substance having a reticular structure or 
not. Besides this reticulation I could generally to some extent trace 
out a concentric striation (cmfr. fig. 23, it was, however, never so 
distinct as it appears in the illustration). 
On examination of carefully prepared sections ^) somewhat more 
light was, however, thrown on the subject, though I must confess^ 
that there are several points in which I could still wish to come 
to more clearness. 
Fig. 24 is a part of a section through two large ganglion cells 
in an abdominal ganglion. We can there see that the membranes 
{cm) enclosing the cells are stout, and are very distinctly marked. 
^) The best preparation-method for this purpose I found to be, fixing in 
chromo-acetO-OSr^iic acid and staining with Heidenhain's hæmatoxylin (cmfr. p. 76), 
or fixing in Lang's sublimate-sokition and staining in Heidenhain's hæmatoxylin 
(cmfr. p. 77). To give the preparations, afterwards, a nuclear staining by DelafieWs 
hæmatoxylin is a very good practice (cmfr. p. 76). 
