18 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
plasm as a reticulum, a complex of fibrils, an emulsion and a zoogloea 
with included granules, and advocates the claims of his own conception. 
After referring to his experiments with artificially produced foams, he 
says, “ to me it seems justifiable to hope that coming generations will yet 
solve the riddle of protoplasm and nucleus, and finally dismiss the 
mystical interpretation of vital processes by referring them to physico- 
chemical processes.” 
Amitotic or Direct Nuclear Division.— Dr. H. E. Ziegler* has 
investigated direct nuclear division in many and various animals, and 
agrees with Flemming as to its import, that it does not lead to the 
formation of new cells, but is a symptom of more or less degeneration, 
sometimes, perhaps, influencing cellular metabolism by the increase of 
nuclear surface. Amitotic nuclear division always represents the end of 
a series of divisions, and is not usually followed by cell-division. The 
nuclei which so divide are usually large, and have been the seat of 
unusually intense secretory or assimilation processes. In Metazoa 
amitotic division is always a secondary process, and in the Protozoa it is 
likely that the same is true. 
Herr M. Lowit f would distinguish regenerating and degenerating 
amitotic division. The former leads to a new formation of nucleus and 
cell, the latter may be associated with secretory and assimilation pro- 
cesses or with the approaching death of the cell. 
Sig. E. Verson J points out that in the spermatogenesis of Bomibyx, 
described by him in 1889, a giant-nucleus gives origin by indirect 
division to secondary nuclei which thereafter multiply abundantly by 
mitosis. Therefore Ziegler’s conclusion is not always true. 
Prof. J. Frenzel § also believes that Ziegler has gone too far. Thus 
in the degeneration of the epithelial cells of the mid-gut of Arthropods 
the half-cell left behind after division retains, in spite of the amitotic 
division, the power of multiplying. He believes that direct nuclear 
division does not necessarily exclude true cell-multiplication. 
Dr. O. vom Path |] discusses the problem of direct division in connec- 
tion with spermatogenesis. Taking the results of his study of the 
spermatogenesis of Astacus along with those of Platner and Hermann on 
Pulmonates, the mouse, and the salamander, he concludes that in all 
cases in which amitotic nuclear division occurs in the testes, it is restricted 
to the marginal or supporting cells. These are not directly concerned 
either in the proper spermatogenesis or in the processes of regeneration. 
The formation of the spermatozoa and the regeneration occur solely by 
mitosis. The marginal or supporting cells are never modified into 
spermatozoa. Therefore the allegation that the amitotic division of 
spermatogenesis is exceptional is not accurate. 
Relations of the Essential Elements of the Nervous System to one 
another .H — Prof. A. Kolliker made this the chief subject of his inaugural 
address to the fifth meeting of the German Anatomical Society. The 
chief conclusions to which he was led are : — 
(1) All nerve-fibres arise from cells, and the structures which have 
* Biol. Centralbl., xi. (1891) pp. 372-89. f Tom. cit., pp. 513-16. 
t Tom. cit., pp. 556-8. § Tom. cit., pp. 558-65. 
|| Zool. Anzeig., xiv. (1891) pp. 331-2, 342-3, 355-63 (3 figs.). 
*|f Verhandl. Anat. Gesell. (Jena), 1891, pp. 2-22. 
