48 Gen. Sub. 
I. GENERAL SUBJECTS. 
number is apt to be disturbed by the occurrence of double or multiple 
chromosomes, or by the division of a chromosome into units of a 
lower order. Epithelial and endothelial cells are most typical ; vom 
Ratii (440). 
Centrosome ; Rompel (458). — The present state of the centrosome 
question ; ELecker (215). 
Centrosomes : Central corpuscles are sharply-defined, solid granules, 
specifically stainable by iron-haematoxylin ; they assimilate, grow, and 
bud ; they have a tendency to form groups ; they unite the threads by a 
centered system ; Heidenhain (225). 
Centrosome in parthenogenetic ova of Artemia , a single centrosome, 
which seems purely a “ Theilungsorgan Brauer (64). 
Archoplasm and attraction-sphere : The archoplasmic portion of the 
attraction-sphere is not a permanent organ ; but the centrosomes retain 
their individuality throughout ; Moore (369). 
Centrosome and archoplasm in Noctiluca j Ishikawa (257). 
Central corpuscle ; Schafer (488). 
Central corpuscle and attractive sphere are morphologically quite dis- 
tinct. Between the two halves of the equatorial plate lies an equatorial 
“lentiile”; Herla (233). 
d. Oell-Division. 
Summary of recent work on the cell and cell-division ; Flemming 
(160), Hill (242). 
Cell-division ; Marshall (332). — Cytomechanics ; Heidehain (227). 
Specific character of cell-divisions : The epithelium of the mylohyoid 
plate, the connective tissue elements of the gills, the red blood-corpuscles 
— e.g., of the Salamander — have characteristic mitoses, as regard form and 
arrangement of chromosomes, position of spindle, and size of centro- 
somes ; Hansemann (220). — Consequences of specific nature of cells ; 
Bard (20). 
“ Mechanism of cell-division : The polar rays are non-contractile, but 
by their growth they displace the poles towards the cell-membrane ; the 
mantle-fibres are contractile ; the central-spindle-rays are non-contractile, 
but elastic, and keep the poles apart against the action of the mantle- 
rays. Apart from the polar rays, two other sets of fibres proceed from 
the poles, viz., the fibres of the central spindle (central fibres) which run 
continuously from pole to pole, and the fibres of the spindle mantle 
(mantle-fibres) which are attached to the halves of the chromosomes. 
The central spindle-fibres are elastic, and keep the poles apart against the 
action of the mantle-fibres, which alone are contractile. The polar 
fibres, by their growth, displace the poles towards the cell-membrane.” 
The paper includes “ An attempt towards a comparative morphology of 
cell-division ” ; Druner (132). 
Effect of pressure on cell-division ; Braem (61), Born (52). 
