712 SUMMARY OF CURRENT RESEARCHES RELATING TO 



uninterrupted system of hollow ducts, and this agrees very closely with 

 the view of Nan sen, who regards the grey substance, as a whole, as a 

 plexus of fine ncrvc-tubes. The woll-kuowii physiological phcnomenou 

 of the dependence of the parts of the organism on the nervous system is, 

 from a morphological point of view, seen more clearly when we know 

 that the nervous material is intermixed with the protoplasm of the cell- 

 substance in all parts of the living body. 



Cell-division.* —Prof, J. Arnold makes a further communication on 

 the division of cell and nucleus in the spleen, and also discusses such 

 processes as diverge from the typical mitos's. lie thus describes " pluri- 

 polar mitosis," " indirect fragmentation," the " homoeotypic " and " hetero- 

 typic " forms of Flemming, and the pathological phases described by Rabl. 

 The distinctiveness of indirect fragmentation is maintained, tliongh it is 

 not denied that transitions occur between it and the forms of pluripolar 

 mitosis. The main object of his present contribution is to show the 

 agreement and the difference between mitosis proper and indirect frag- 

 mentation. 



Cell-membrane.t — M. M. Ide has invcstignted the nature of the mem- 

 brane in the cells of the mucous Malpighian layer of the epithelium. 

 The best material was obtained from embryonic epithelium in the skin 

 and digestive tract. 



He regards the reticulated peripheral layers of the cells as cellular 

 membranes in the true sense, and that for two reasons : first, because tliey 

 exhibit the general and typical structure of cellular membranes ; and 

 further, because they are derived from the primitive membrane of the 

 young cells by a simple cleavage. 



As to the bridges which connect the cells, he regards them as forming 

 part of the cellular membrane. They are in substantial continuity with 

 its reticulum ; they present the same structure as its trabecular, and are 

 derived, like the enveloi^e itself, from the original membrane. 



Goblet-cells of Intestine of Salamander.j — Herr J. Steinhaus has 

 investigated the so-called goblet-cells in the epithelium of the intestine of 

 Salamandra 'maculosa. They are neither exclusively epithelial cells under- 

 going mucous degeneration, nor cells modified into unicellular mucus- 

 glands. They are partly the one, partly the other. If no second nucleus 

 be present in the cell it completely degenerates ; if one be present the 

 cell functions as a gland, and is regenerated after secretion. In forming 

 a goblet the nucleus undergoes mucous metamorphosis ; the theca is iden- 

 tical with the nuclear membrane, the foot of the goblet is never inclosed 

 in the theca, but is protoplasmic to its end. 



Any cylindrical cell of the intestine may become a goblet-cell, and 

 the change, though not yet understood, is in association with physiological 

 processes in the intestine. The more energetic the processes, the greater 

 the number of goblet-cells. As the number increases greatly in certain 

 pathological processes (e. g. intestinal catarrh), it is of importance to 

 understand the conditions of the development of goblet-cells. 



Micro-Chemistry of Nerve- cells. — Prof. M. Flesch § sums up the re- 

 sults of invcbtigations made by himself and others on the differences in the 



* Arch. f. Mikr. Anat., xsxi. (18S8) pp. 541-Gi (3 pis.). 



t La Cellule, iv. (18S8) pp. 403-33 (1 pi.). 



: Arch. f. Aiiat. u. Physiol. (Physiol. Abth.), 1888, pp. 311-22 (3 pis.). 



§ MT. Naturf. Gescll. Utrii, 1888, pp. 192-9. 



