14 OYSTERS AND DISEASE. 



(Fig- 9)- Barfurth and Frenzel have shown the presence of three kinds of cells in the 

 glandular epithelium of the molluscan liver, viz. — " Kornerzellen," " Fermentzellen," and 

 " Kalkzellen " ; but not all of these are present in all cases. Frenzel* states in regard 

 to the common oyster : — " (a) Die Kornerzellen haben einen Durchmesser von circa 32 

 mikr. Die Korner sind gelb- bis rothlich-braun gefarbt, 3 bis 4 mikr. gross und kugelig. 

 Die granula sind wenig zahlreich und punktformig. (/>) Ferment- (Keulen-) Zellen 

 nicht aufgefunden (Marz). (c) Kalkzellen fehlen." 



We find two kinds of glandular cells in the liver of our oysters — the ordinary 

 large granular liver cells (Kornerzellen), and smaller, more deeply-staining cells, which 

 we take to be Frenzel's " Fermentzellen." The relative positions, sizes, and appearance 

 of these cells is shown in Figs. 6, 7, 8, &c, on PI. III. We have in some cases (Fig. 12) 

 observed the presence of small green pigment"]- granules in the larger cells, but have 

 not found any giving an iron reaction. Here and there, in the vesicular connective 

 tissue between the caeca, may be seen (Fig. 10, e. chl.) the aggregations of dark green 

 granules described as " entero-chlorophyll " by MacMunn. Whether this pigment is a 

 modification of the yellow hepatochrome described by Miss Newbigin in the liver and 

 integument of Crustacea, and which apparently may vary from red to green in colour, 

 or is a derivative of chlorophyll from vegetable food, as held by MacMunn, and this 

 seems very probable, cannot be determined without further investigation both spectroscopic 

 a-nd chemical. In the meantime, enterochrome (see Newbigin, Quart. Journ. Mic. Sci., 

 November, 1S98) certainly seems the more appropriate name for this pigment, or set 

 of pigments. 



* Mikrographie der Milteldanndruse (Leber) der Mollusken. Nova Acta Leop.-Carol. Akad., Bd. XLVIII., 

 No. 2, 1886. 



+ Ryder also described green pigment in the inner ends of the liver cells in 1893. 



