270 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
gested. The other stains like the chromioles, and is given the name 
of the chromoplast. The chromoplast presides over the formation of 
the chromosomes, while the lininoplast is a storage reservoir of linin 
granules. 
Structure of Protoplasm.* — Prof. O. Biitschli has found in Nageli’s 
‘ Theorie der Garung’ (1879), pp. 152— 6, a theory as to the structure 
of protoplasm, which in all essentials is identical with Biitschli’s own 
“ foam theory.” Nageli expressly stated that in certain cases the foam- 
like or reticulated structure is quite distinct, and that a gradual transi- 
tion may be observed between this and an apparently homogeneous 
structure. He also added the statement that such a foam structure is 
probably always present, though it may not always be distinctly visible. 
Protoplasm of Epithelial Cells.f — H. Bolsius has a note on a com- 
munication read by Prof. Heidenhain before the Physik-med. Gesell- 
schatt Wiiizburg, in January of the present year. Prof. Heidenhain 
described a peculiar fibrillar appearance in the epithelial cells of the 
intestine of the frog, and Bolsius points out that cells of similar struc- 
ture were previously J described by him in the unpaired gland of 
Hsementeria officinalis. 
Structure of Protoplasm.§ — Dr. Karl Herxheimer has investigated 
the cells of the epidermis in man, with special reference to the general 
question of the structure of protoplasm, and the characters of the fibrils 
previously described in human epidermal cells. The research was 
limited to cells removed from living subjects, especially to extirpated 
condylomata. In such material, when freshly excised and sectioned 
in a freezing microtome, the cells displayed no fibrils, but merely a 
distinct protoplasmic reticulum. This reticular appearance is however 
an optical effect, indicative of the existence of a foam structure. The 
protoplasmic fibrils show the same staining reactions as the meshes of 
this network, and the author is of opinion that the appearance some- 
times of fibrils, sometimes of a network, is due not to structural differ- 
ences, but to differences in the methods of staining and fixing, and that 
in normal human epidermal cells the protoplasm has a honeycomb 
structure, whatever may be the appearauce presented by it. The “ proto- 
plasmic fibrils ” are probably formed of the material which constitutes 
the walls of the chambers of the honeycomb. 
Structure of Nerve-cells. || — Herr Vladislav Ruzicka has investi- 
gated the so-called Nissl’s corpuscles of nerve-cells. He finds that they 
are not represented in living cells, but are artificial products dependent 
on the methods of staining employed (staining with tolui din-blue followed 
by decoloration in water and alcohol). He finds further that the motor 
cells of the anterior horn on the spinal cord in the ox and in the dog 
do not all possess longitudinally striated protoplasm, so that this struc- 
ture cannot be characteristic of motor cells. As to the relations of the 
constituent cells of the spinal cord, he finds that they may be united 
to one another by anastomoses, and that they also send out extremely 
* Zool. Anzeig., xxii. (1899) pp. 145-6. f Tom. cit./’pp. 142-5 (2 figs.). 
X La Cellule, xii. (1896). 
§ Arch. Mikr. Auat., liii. (1899) pp. 510-46 (1 pi.). 
|l Tom. cit., pp. 485-510 (1 pi.). 
