ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
25 
Chromatin of Sympathetic Ganglia.* — Dr. F. Vas finds that the 
chromatin of the sympathetic nerve-cells has a definite structure, that its 
development keeps pace with that of the organism as a whole and with 
that of the nerve-cells in particular, that the associated pigment expresses 
a specific property of individual species, and that in man the chromatin 
is partly destroyed in old age. The stimulated cell differs from the 
unstimulated in several features, especially in the enlargement of the 
nucleus and its movement towards the periphery. 
Blood of Amphibia. f — Herr M. C. Dekhuyzen finds five distinct 
kinds of cells in the blood-plasma. The distinctive characters of the 
adult cells appear only gradually, so that there are unexpectedly great 
differences between the youngest and the fully developed stages. In 
analogy with Lowit’s nomenclature he uses the ending “ blast ” for 
young forms, and “ cyt ” for those w r hich are adult. He distinguishes 
(1) haemoglobin-free erythroblasts, and erythrocytes or chromocytes, 
known by their nucleolus ; (2) thromboblasts and thrombocytes, as the 
“ spindles ” of Eberth and Schimmelbusch may be called ; they are 
known by their mitochrom ; (3) finely granular leucoblasts or leuco- 
cytes, known by their pseudopodia and by the tendency of the nucleus 
to polymorphism and polymerism : (4) eosinophilous leucoblasts (with 
/2-granulations) and leucocytes (with a-granulations), known by their 
granulations and the same nuclear characters as (3); (5) klasmatoblasts 
and klasmatocytes, known by their granules. The various characters of 
these cells are treated in detail, and it is urged that there is no evidence 
of any intermediate stages between the different kinds. 
Cerebro-Spinal Ganglia4 — According to Prof. A. Van Gehuchten 
the application of the new methods of treating nerve-cells has resulted 
in showing that the nerve-cells of the spinal ganglia of most Fishes are 
opposito-bipolar ; each pole is continuous with the cylinder-axis of a 
nerve-fibre, one of which passes to the medulla and the other to the 
periphery. The nerve-cells of the spinal ganglia of other Vertebrates are, 
in the adult, all unipolar ; the single prolongation bifurcates, at a vary- 
ing distance from the cell, into a central and a peripheral prolongation. 
In Cyclostomatous Fishes there are in the spinal ganglia of the adult 
not only both the above kinds of cells, but also others which are inter- 
mediate ; and this shows that a bipolar may be transformed into a unipolar 
cell. The same fact is observed in the embryos of Mammals, Birds, and 
Beptiles. At a certain period in development all the nerve-cells of the 
spinal ganglia are opposito-bipolar, as in Fishes ; in the course of deve- 
lopment the form of the cell is modified, and the bipolar cell becomes 
unipolar. The morphological difference, therefore, which exists between 
the spinal ganglia of Fishes and other Vertebrates is more apparent 
than real ; the lower forms retain permanently a condition which is 
transient in the higher. 
In all Vertebrates, then, the spinal ganglia have the same signifi- 
cance ; the cells which form them give rise, in one way or another, to 
two prolongations which become the cylinder-axes of two nerve-fibres. 
* Arch. f. Mikr. Anat., xl. (1892) pp. 375-89 (1 pi.), 
t Verhandl. Anat. Gesell., 1892, pp. 90-103 (1 pi.). 
X Bull. Acad. Eoy. Belgique, lxii. (1892) pp. 117-54 (11 figs.). 
