462 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
embryo onwards ; and the organs in which they occur abundantly are 
simply localized areas of multiplication. 
The leucoblasts, on the other hand, do not appear to multiply by 
mitosis ; what has been described as such is the mitosis of fixed cells or 
of erythroblasts. They persist from embryonic life onwards, multiplying 
by amitosis in special localities, but never arising from fixed cells. 
Prof. Lowit then describes in detail the precise disposition of the 
erythroblasts and leucoblasts in the various organs involved. 
According to Lowit the red blood-corpuscles arise (as long as they 
continue nucleated) from the mitosis of other erythrocytes and even- 
tually from the colourless erythroblasts, and the blood-forming organs 
mentioned are the special areas for this multiplication. Similarly, the 
white blood-corpuscles arise in the haematopoetic organs from leuco- 
blasts, quite distinct from erythroblasts. Multiplying by amitosis, 
they pass by the lymph or venous blood into the general circulation 
as mononuclear leucocytes, or they may be modified into polynuclear 
elements — a degenerative rather than a regenerative change. 
Structure of Nerve-fibres.* — Dr. Ph. Owsjannikow corroborates 
what has been observed by M. Joseph and Jakimowitsch, that the axial 
cylinder may exhibit a distinct transverse striation like that of striped 
muscle. He has observed this in the frog, rat, &c., and in the non- 
medullated nerves of the crayfish. In the lamprey, however, it was 
distinctly seen that the striation occurs only on the outer surface of the 
axis-cylinder, and does not affect the primitive fibrils. Owsjannikow 
emphasizes the fact that treatment of nerve-fibres with silver alters them 
greatly, and gives origin to artificial structures. The primitive fibrils 
are more distinct in the lamprey than in other animals : they exhibit 
varicosities, and are separated by an intermediate substance. The 
Ewald-Kiihne network is a normal, certainly not an artificial, structure. 
Muscle-spindles-t — Herr A. A. Christomanos and E, Strossner 
discuss the various opinions held in regard to muscle-spindles. They 
describe their characters in Man, in embryonic, adolescent, and adult 
subjects. Against the supposition that they are due to physiologically 
atrophied muscle-bundles, many considerations are adduced, while other 
facts seem to show that the spindles are actively concerned in the growth 
and development of the muscle-fibres. 
Relation of Animal Protoplasm to Haemoglobin 4 — Herr Giirber 
emphatically denies the conclusion of A. Schwartz that it is a general 
property of animal protoplasm to form and to destroy haemoglobin. The 
results of experiments with the cells of liver and spleen do not tally with 
those of Schwartz. A solution of haemoglobin is indeed decolorized 
and re-coloured by spleen and liver cells, but that is explained as 
follows. The haemoglobin is changed for the most part into met-haemo- 
globin and is taken up by the cell-masses in the same way as by 
charcoal. To act thus, the “ Zellbrei ” produced from spleen cells is 
naturally suited ; that produced from liver cells only does so after the 
addition of water. When putrefaction alters the physical nature of the 
* Melanges Biol. (Bull. Acad. Imp. Sci. St. Petersb.) xiii. (1891) pp. 101-12. 
t SB. K. Akad. Wiss. Wien, c. (1891) pp. 417-35 (3 pis.), 
j SB. Phys.-med. Gesell. Wurzburg (1891) pp. 114-22. 
