572 H. p. KJERSCHOW AGERSBORG 



3. In the proximal region of the cell may be seen the nucleus, 

 small and shrunken, containing a small nucleolus, 

 and lodged at the base of the cell. 



4. A state of refilling now ensues (C). The nucleus begins to 

 enlarge and then a homogeneous cytoplasmic substance is 

 accumulated around it, which then spreads throughout the 

 cell. At the same time the micromeres of the vacuolated 

 cytoplasm of the cell increase in size. 



That the nucleus takes a very active part in the formation 

 of the mucinous substance is clearly evident, but the micro- 

 meres of the cytoplasm seem also to take an active part in 

 the refilling of the cell as indicated by the growth of the 

 micromeres formed in the meshes of the reticular network 

 of the cytoplasm before the nucleus has assumed its normal 

 condition. In semi-vacuolated cells, i.e. cells which are in 

 the state of refilling, the nucleus is intermediate in size and 

 granulation to those described under (B). It is of interest to 

 note some of the findings of Lange (1902) from his studies of 

 the structure and function of the ' Speicheldriisen ' of gastero- 

 pods. This author found that the cells of the glands showed 

 great differences during feeding as compared with periods of 

 starvation. Some of these phases of activity of the cell are 

 quite similar to those recorded above for the mucous gland 

 of M . 1 e o n i n a . Lange says : 



In alien Stadien der Fiitterung und auch des Hunger- 

 zustandes finden sich nie samtliche Sekretionszellen auf dersel- 

 ben Sekretionsstufe. Es kommen in jedem Stadium der 

 Fiitterung und des Hungers alle Stadien vor, doch in ver- 

 schiedener Haufigkeit. Der Kern nimmt innigen Anteil an 

 der sekretorischen Thatigkeit, indem im Anfang seine Membran 

 sich auflost und sein Inhalt sich mit dem Protoplasma ver- 

 mischt, sodass der erste sekretorische Vorgang sich am Kern 

 bemerkbar macht. Die von Barfurth als ' Speichelkugeln ' 

 bezeichneten Gebilde sind Sekretvakuolen, welche angefullt 

 sind mit muciginer Substanz. Man kann deutlich verfolgen, 

 wie sich das Mucigen in diesen Sekretvakuolen zu Mucin 

 umwandelt. 1st das Mucin gebildet, so verliert der Kern 

 seinen Turgor wohl durch Austritt von Kernfllissigkeit. Dabei 

 steht das Kerninnere stets im offenen Zusammenhang mit dem 



