ZOOLOGY AND BOTANY, MIOROSOOPY, ETC. 405 



After pointing out that the cell consists of a membrane inclosing 

 a reticulated protoplasm, the " cytoplasm," containing in its meshes 

 numerous granules, the " enchylema," he describes in greater detail 

 the structure of the nucleus itself. This too consists of a membrane 

 inclosing a protoplasmic reticulum, the " caryoplasm," in which is a 

 continuous and greatly twisted filament of " nuclein." Carnoy gives 

 numerous figures of the nucleus in many difierent varieties of cells. 

 The " nuclein " (or *' chromatin ") exists as a continuous filament, and 

 not as a network, as is usually stated and figured ; it consists of a 

 wall or case with contents. The wall is readily seen in cells of the 

 tissues of insects, and is rendered very distinct by means of methyl- 

 green; by chemical tests it is found to consist of plastine. The 

 contents are sometimes homogeneous, sometimes formed of rings or 

 discs. As a rule this " nuclein " is coiled throughout the nucleus ; 

 but it may sometimes be centralized and then forms a nucleolus. 



The " caryoplasm," like the " cytoplasm," which it resembles in 

 chemical composition, consists of a reticulum of protoplasm, in the 

 meshes of which is the " enchylema." No " chromatic reticulum " is 

 really present, such an appearance being due to faulty methods of pre- 

 paration or of staining. Methyl-green is the best staining agent for 

 the purpose. "When the nucleus divides, the cytoplasm becomes 

 part of the caryoplasm of the new cells, and part of the caryoplasm 

 of the old cell becomes the cytoplasm of the new nuclei. The 

 nuclear membrane is completely closed ; the appearance of pores in 

 it is due to a reticulum on its surface. Thus a nucleus differs from a 

 cell only in having the " nuclein " instead of a nucleus. 



Goblet-cells and Leydig's Cells.*— Dr. J. H. List emphasizes 

 the frequent ambiguity in the use of the term "mucous-cells" 

 (" Schleimzellen " ), and proposes the disuse of the phrase, and the 

 consistent distinction of (a) goblet-cells and (b) Leydig's cells. 



(a) The gohlet- cells, distinguished by F. E. Schulze into those 

 with, and those without a definite basal portion containing the 

 nucleus (" befusste " and " unbefusste "), are first discussed, and the 

 various modifications due to constriction, presence or absence of neck 

 and of stoma, &c., are noted. In those without a definite basal por- 

 tion the nucleus lies in the theca close to the basal wall, and two 

 types are distinguished, according as the thecal wall is or is not 

 continued into a stalk. In some cases Dr. List saw hints of a con- 

 nection between the stalk and nerve-fibres. The best instance of 

 goblet-cell with a distinct basal portion containing the nucleus was 

 afforded by the cells in the upper lip of Cobitis fossilis. Within the 

 theca he distinguishes the threadwork of chromophilous strands 

 ("Filarmasse"), and the apparently homogeneous, viscid, less readily 

 stainable intermediate substance (" Interfilarmasse "). No direct con- 

 nection between the cellular threadwork and the nuclear network 

 was observed. The best results were obtained by double-staining 

 with hfematoxylin-glycerin and eosin. 



(h) Leydig's cells may be thus summarily distinguished from the 



♦ Arch. f. Mikr. Anat., xxvi. (1886) pp. 543-52 (1 pi.). 



