348 PROCEEDINGS OF THE ACADEMY OF [MaV, 



4. The iutestiual epithelium is a syucytium, the cytoplasm 

 being continuous from one cell to another. Intercellular fibres, 

 together with furrows in the basement membrane and intima, serve 

 to mark off the cells distinctly. 



5. The cytoplasm of the intestinal cells is alveolar in structure. 

 Between the alveoles is a homogeneous substance which precipitates 

 as a finely granular coagulum. Intracellular fibres run between 

 the alveoles; at the luminal side of the cell they are parallel and 

 are greatly thickened so as to form a palisade from the intervals in 

 which the cytoplasm may be excluded. 



6. The nucleus of the intestinal epithelial cells is normally 

 spherical in all physiological conditions ; it is alveolar in structure 

 in the fresh condition, and contains in "perfectly" fixed material 

 numerous large granules of chromatin. 



7. In the moult of the chitinous lining of the intestines the 

 coelomic side of the epithelial cell rarely suffers any change. The 

 luminal side undergoes the following changes : the thickened ends 

 of the fibres disappear; the alveolar structure at the same time 

 becomes concealed by a fluid substance which precipitates in killing 

 fluids in the form of fine granules. The new chitin is j)robably 

 formed by some process of hardening this substance. After the 

 new lining begins to appear, delicate fibres are seen on the luminal 

 side of the cell. The strength of the palisade on the luminal side 

 varies directly with the time from the last moult. 



8. The land isopods after a period of starvation will eat various 

 kinds of pure foods. 



9. Starving for a considerable time (three Aveeks) produces the 

 following changes in the intestinal cells : the interalveolar substance 

 is reduced in quantity; the cytoplasm may Avithdraw from the 

 luminal side, leaving elongated spaces between the fibres ; vacuola- 

 tions may appear elsev^here in the cytoplasm. 



10. After feeding a starved animal for ten minutes on finely 

 chopped raw beef, before any food is visible in the cells, definite 

 masses of fine granules appear about the nucleus. Some of these 

 at least come from the nucleus. They increase in number up to 

 thirty hours after feeding. We have designated this granular 

 substance as an intracellular ferment. 



11. Eight hours after feeding a starved animal with finely 

 chopped raw beef, albumose appears in the intestinal cells. The 



