162 SUMMARY OF CURRENT RESEARCHES RELATING TO 



an active (muscle-like) function, but refer the process of division to 

 the chemico-physical properties of cytoplasm and nucleoplasm. It 

 seems to him hardly possible to get beyond this vague generalisation 

 until the chemical phjsiology of the cell is more advanced. 



Spindle-Residues in Cell-Division.* — P. Bouin distinguishes the 

 spindle-residue formed between two daughter-cells at the expense of the 

 central-spindle-fibres and amalgamating into the intermediate corpuscle, 

 from other spindle-residues built up after the telophase and after the 

 disappearance of the vestiges of the karyokinetic spindle. 



In the divisions of the spermatocytes of the first order in Lithobius 

 forficatus there are three successive spindle-formations : (1) a primary 

 protoplasmic spindle, extending during the prophase between the central 

 corpuscles, but disappearing before the end of the prophase ; (2) a 

 secondary spindle, the true karyokinetic spindle, formed at the expense 

 of the linin-framework of the nucleus ; and (3) a tertiary spindle or 

 spindle of separation, formed after the disappearance of (2), from fibrils 

 differentiated de novo along the whole equatorial region, and giving rise, 

 as the cell-membrane grows in, to a spindle-residue. This formation is 

 not referable to the karyokinetic spindle ; it is a new differentiation 

 characteristic of the telophase. 



Trophospongia. — E. Holmgren describes canal-like " trophospongia " 

 in the cells of the epididymis of the white mouse and in the cells of 

 the bile-duct epithelium of the snail. They occur exclusively within 

 the granular or vacuolar triangular space to the external side of the 

 nucleus, and do not show any direct connection with the fibrillar or 

 threadwork apparatus of the cell. The same disposition was found in 

 the epithelial cells of the mammalian uterus and thyroid gland. 



" Intracellular Threads " in Ganglion-Cells of Electric Organ of 

 Torpedo.J — B. Solger returns to a study of these structures to which he 

 gives an interpretation somewhat different from that in his paper of 

 1897. § He thinks there is a coherent system of canaliculi and spaces 

 penetrating the cell-substance, here and there opening externally into 

 the pericellular space, and often including thread-like structures which 

 stain deeply with iron-haematoxylin, and sometimes fill up the lumen. 

 His point is, that the granular threads are in connection with the intra- 

 cellular canaliculi and spaces, are, in fact, concretions or precipitates 

 within some of them. 



Intranuclear Space in Liver-Cells. |j — Gustav Schlater find3 that 

 the nucleus of the hepatic cell is very elaborate. It includes a space 

 ellipsoidal like itself, and with the same centre. Between the surface of 

 this space and the suiface of the nucleus is the body proper of the 

 nucleus. This includes six nucleolar apparatuses (Kernkorperchenappa- 

 rate), quite definitely disposed, so that the lines joining them form a 

 regular octahedron. More superficially is the so-called chromatin net- 



* Arch. Zool. Expe'r., x. (1902) Notes et Revue, No. 7, pp. cvi.-eix. 

 t Anat. Anzeig., xxii. (1902) pp. 83-6 (2 figs.). 

 % Morph. Jahrb., xxxi. (1902) pp. 104-15 (1 pi.). 



§ SB. Med. Ver. Greifswald, May 1S97 ; Tagbl. Naturforsch. Vers. Braunschweig, 

 Sept. 1897. II Anat. Anzeig., xxii. (1902) pp. 249-59 (1 fig.). 



