22 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
fibrils of mitosis arise by a differentiation of this framework. A reti- 
cular arrangement is suggested, but not conclusively demonstrated. The 
fibrils around tbe centrosomes have an exquisite microsomal structure. 
The microsomes occur in groups on the fibrils at equal distances from 
the centrosome, and thus a concentric system appears. This mitom- 
system is indubitably the seat of the contractile forces of the plasm. 
The interfilar substance is probably trophic. The centrosomes are 
specific and essential parts of the cell, morphologically independent and 
persistent “ organs,” serving as insertion centres for the radii. The 
authors support on the whole the conclusions of Flemming, vanBeneden. 
and Heidenhain ; andjbesides stating their own results, give a useful — if 
somewhat prolonged — account of the views of others. 
Protoplasm of Nerve-Cells.*' — Dr. S. Ramon y Cajal finds that the 
cytoplasm of many nerve-cells, both of Vertebrates and Invertebrates, 
includes numerous chromatin patches. These are possibly of nutritive 
value, for the conducting part is the achromatic spongioplasm. The phy- 
logenetic and ontogenetic phases of the distribution of chromatin in the 
cytoplasm of nerve-cells are : — (1) diffuse and inconspicuous, (2) peri- 
pheral, (3) circumnuclear and peripheral, (4) throughout the whole cell. 
There is a relation between the dimensions of the patches and the 
volume of the protoplasm, but not between the chromatin differentiation 
and the functional dignity of the cell. The nucleus of nerve-cells 
becomes simpler as differentiation advances, the nuclein being concen- 
trated to one or two spherical nucleoli. 
Nerve-Endings of Duck’s Bill.| — Dr. L. Szymonowicz finds (1) that 
the tactile cells ( Tastzellen ) of Grandry’s and Herbst’s nerve-corpuscles 
are of connective-tissue origin ; (2) that this differentiation of connective 
cells occurs under the influence of the nerve-fibres; (3) that Merkel’s 
corpuscles (of epithelial origin) are sharply distinguished from Grandry’s 
and cannot be brought into the same histological or histogenic group. 
Inner Root-Sheath and Papilla of the Hair.}-— Herr Gunther shows 
that the several layers of the skin are represented not parallel to the 
longitudinal line of the hair and the inner root-sheath, but at right 
angles thereto. In the inner root-sheath the basal cell = stratum 
cylindricum ; the adjacent cells without keratohyalin = the lower 
cells of the stratum dentatum ; the cells with keratohyalin = the upper 
cells of the stratum dentatum and the cells of the stratum granulosum. 
The limit of cornification in the internal root-sheath corresponds 
to the stratum lucidum, and the horny part to the stratum corneum. 
The inner root-sheath, [with its matrices, is to be considered as an 
elongated piece of epidermis of protective, guiding, and fixing function. 
Pigment-Cells.§ — Dr. A. Fischel refers to a recent paper by Prof. 
Lubarsch, where his views are placed in incorrect antithesis to those of 
Reinke. The main difference between Fischel’s conclusions and Reinke’s 
seems to be that Fischel finds two kinds of pigment-cells in the sala- 
mander’s peritoneum, while Reinke finds only one kind. Fischel’s two 
* Ann. Soc. Espan. Hist. Nat., v. (1896) pp. 13-46 (6 figs.). 
f Arch. f. Mikr. Anat., xlviii. (1896) pp. 329-58 (1 pi.). 
X Verb. Anat. Ges. X. Vers, in Anat. Anzeig. Erganzhft. xii. (1896) pp. 183-9 
(5 figs.). § Anat. Anzeig., xii. (1896) pp. 526-8. 
