48 SUMMAEY OF CORRENT RESEARCHES RELATING TO 



The secretion occurs normally in superficial cells in which a stoma has 

 been formed as the result of j^ressure and absorption. The secretion is 

 apparently determined by what appears like a gradual coagulation. No 

 nuclear modifications were observed. The secreted mass consists chiefly of 

 the interfilary substance, but the threadwork was also represented. The 

 secretion may be repeated more than once, but finally the whole cell is 

 expelled. This degeneration is associated with epithelial regeneration, and 

 even still functional cells may be expelled. 



In regard to the development of the goblet-cells, Dr. List's results go to 

 show that they are modified from epithelial cells of the subjacent layers. 

 The very varied occurrence of the cells is then discussed. The author 

 maintains the entire distinctness of the goblet-cell types, and the distinc- 

 tions which he draws between them and Leydig's cells have already been 

 noted in this Journal. He differs from Schiefferdecker in maintaining 

 further their entire distinctness from the cells of mucous glands. 



Some interesting facts are communicated in regard to the artificial pro- 

 duction of goblet-like cells by the action of reagents upon ordinary 

 epithelial cells. As to the physiological import of the cells, about which 

 there has been so much variety of oiDinion, the author only commits himself 

 to regarding them as unicellular glands of a perfectly specific character. 

 The action of various reagents is finally noted. 



Endogenous Cell-multiplication.* — M. A. Jaworowski has investigated 

 the development and histogenesis of Chironomus and other organisms with 

 special reference to the endogenous multiplication of cells. 



I. (a) The reproductive organs of Chironomus arise dorsally on the 

 ninth ring in the form of a protoplasmic mass composed of two cells and 

 surrounded by a fine homogeneous membrane. Within each of these 

 two cells four daughter-cells arise, and the endogenous method of multipli- 

 cation is constant. Each ovarian tube is primitively spherical ; it elongates 

 gradually by the formation of new cells at the anterior pole, and is suc- 

 cessively constricted at the limit of each new centre of development. The 

 thread-like tube which results contains protoplasm and cells which give 

 rise to the terminal filament of the ovarian tube. The centre of each 

 constriction is occupied by a cell increasing at the expense of its neighbours 

 and forming the ovum. The author maintains that the ovarian tubes of 

 vertebrates ai'e similarly formed. 



(h) Muscular sheath of the ovarian tubes. — Among the mother-cells which 

 give rise to the ovarian tubes there is a portion of residual protoplasm 

 of the primitive cell. This always forms little nucleated cells which 

 become muscle-fibres. These elongate in all directions, and form a single- 

 layered muscular network round the ovarian tubes. 



(c) Tlie terminal filaments and the efferent duels are then described, 

 without, however, establishing much that is new. From a single primitive 

 cell, according to Jaworowski, the entire organ arises. All the cells — 

 ovules, epithelial, and vitelline — are homologous. The latter never serve 

 to nourish the ovules except in a wholly indirect way. 



(cZ) The egg-envelope is not due to peripheral ovules or epithelial cells, 

 but solely to the surrounding protoplasm of the primitive cells. The 

 epithelial cells only form markings on the envelope. The author, in 

 concluding his detailed survey of the development of the reproductive 

 organs, refers the rapid death of the insects after egg-laying or sperm 

 emission to the fact that the abdominal cavity, distended with reproductive 

 elements, cannot retract immediately after the expulsion of the latter, and 



* Arch. Slav, de Biol., i. ( 188G) pp. 641-51, from Ann. Acad. Sci. Cracovie, 1885. 



