ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
37 
Cell-Studies.* — Dr. F. Reinke refers first to Kromayer’s conclusion 
that the chromatophores in the epidermis of mammals, e. g. man, are not 
cells, but fibrils of epithelial cells, modified into pigment, and that one 
cannot tell where the fibres of one cell end and those of another begin. 
Reinke cut sections of skin hardened in alcohol, stained them for several 
days in concentrated alcoholic solution of safranin half diluted with 
water, washed them, left them 1-3 hours in potassium iodide, and dif- 
ferentiated them with picric acid in absolute alcohol. So prepared the 
sections show the body of the cell, the fibrils traversing it, and the inter- 
cellular bridges, with nodes on the middle of them. The limits of the 
cells are quite distinct. Perhaps the nodes represent multiple cell- 
plates. 
Reinke then describes the system of radiating threads in leucocytes, 
the formation of collagen and elastic fibres and granular substance in 
fixed connective-tissue cells ; he discovers small bodies, like the tropho- 
blasts of plants, which appear to form the organic substrata of the pig- 
ment-granules in animals. 
Like Heidenhain, he finds a complex structure in the “ nuclear sap ” 
(parachromatin of Pfitzner, paralinin of Schwartz). Using the lysol 
method and others, he comes to the conclusion that the linin is the 
nuclear plasma, and that it becomes web-like or foam-like, owing to the 
presence of granules imbedded in it. These granules are partly of 
chromatin, partly of another substance which has remarkable properties 
and to which he gives the name cedematin. Of this substance he has 
much to say, and he shows that a series of nuclei may be differentiated 
in relation to the state of the oedematin present and the manner in 
which the lysol acts. 
Nature of the Central Spindle.|— Dr. L. Driiner regards the 
central spindle as a supporting framework which not only fixes the poles 
against one another, but by its growth determines their distance, altering 
in form according to the strain on the fibres at different moments. 
Variations in Mitosis. J — Herr V. Herla has studied the variations 
in the mitosis of Ascciris megalocephala. In the univalens variety he 
noted prophases with two chromosomes in each pronucleus, prophases 
with a longitudinal division of the chromosome within the pronucleus, 
metakinesis and dyaster also with traces of the precocious longitudinal 
division of the chromosome, metakinesis and dyaster, with the two halves 
progressing at unequal rates towards the poles, reconstruction associated 
with a secondary division, peculiar bilobed nuclei, ova with three chro- 
mosomes, ova with six chromosomes and abnormal polar bodies, and so 
on through a long list. 
In an ovum with three chromosomes the development remains normal. 
An ovum of the bivalens variety may be fertilized by a spermatozoon of 
univalens variety, and develope. To say the least, one must be careful 
not to exaggerate the exactness with which the chromatin elements 
represent the hereditary material. 
The doubling of the chromosomes is regarded as a manifestation of 
* Arch. f. Mikr. Anat., xliii. (1894) pp. 377-422 (3 pis., 1 fig.), 
t Jenaische Zeitschr. f. Naturwiss., xxviii. (1894) pp. 469-74. 
t Arch. Biol., xiii. (1893, published July 1894) pp. 423-520 (5 pis.). 
