GLANDULAR EPITHELIUM AND DIVISION OF NUCLEI. 417 



from it, and it is likewise established by Strieker, that the 

 nucleus of those cells is during life in direct anatomical 

 continuity with the cell substance, and further that by the 

 appearance of a membrane a central portion of the cell 

 substance becomes temporarily differentiated as nucleus. I 

 have also mentioned on a former page that the giant nuclei 

 of the gland cells of newt show local contractions of their 

 reticulum. The connection of the fibrils of the dividing 

 nucleus with the cell substance and the contractility of both, 

 seems to me to explain also the peculiar appearances 

 described by Auerbach as " karyolitic figure " and observed 

 by many others (Flemming, Fol, Biitschli, Strasburger, 

 O. Hertwig, and others) in dividing nuclei of ovum and 

 other cells, viz. a radiar arrangement of fibrils of what 

 corresponds to the cell substance towards the nucleus, when 

 single as well as after division — in the former case as a 

 single, in the latter as a double " karyolytic figure." We 

 have to assume that, owing probably to contraction of the 

 intranuclear network, the fibrils of the intracellular reticulum 

 are drawn towards the former. Whether at the same time 

 an exchange of the two substances takes place, or whether 

 the nucleus alone takes in matter from the cell, it is difficult 

 to decide ; both seem probable from theoretical considerations 

 so thoroughly discussed by Auerbach, Strasburger, Biitschli, 

 Flemming, and Schleicher. 



A point not less interesting is the question, whether the 

 division of the nucleus takes place in all cells of the epi- 

 dermis of adult newt after the same complicated manner 

 as described in the preceding, or whether there is in addition 

 another simpler mode, so often mentioned in normal and 

 pathological histology as that of simple cleavage. Flemming 

 proposes the term "indirect" multii)lication of the nucleus 

 for the former complex mode, and "direct" for the latter 

 simple mode, and we shall accept these terms in the following 

 description. 



Auerbach and Eberth accept such a direct mode of divi- 

 sion, Flemming questions it, although he does not think it 

 quite impossible. This last named author describes forms 

 of nuclei which might be taken as indicative of simple cleav- 

 age, viz. ordinary nuclei kidney-shaped and lobed, or beset 

 with more or less deep constrictions ; but he finds reasons 

 to believe that" these are only temporary appearances due 

 probably to movement. 



As I mentioned on a former page the very rapid shedding 

 of the superficial layer of the cells of the epidermis led 



