340 



PROCEEDINGS OF THE ACADEMY OF 



[May, 



intestiual cells. Examined fresh, large oily-looking globules are 

 always to be found iu the projecting cells, which, after most fixa- 

 tions, are represented by mere vacuoles. These increase in size 

 from the base toward the apex, and often quite completely occupy 

 the apical end, displacing the ground structure itself (fig. 22). 

 Between the vacuoles, in well fixed cells, are to be seen small alve- 

 oles which, if the vacuoles be large and close together, are more or 

 less distorted by the pressure. Between the alveoles and covering 

 them, often so densely as to obscure them, are tiny granules repre- 

 senting interalveolar substance and alveolar contents. After some 



Fit?. 22.— Cell a of fig 21 X 600. Escape of the secretion by rupture 

 of tlie membrane at the free end of the cell. Vac, vacuoles from which 

 the globules of zymogen have been dissolved by the fixing fluid and 

 other reagents ; Zym., zymogen granules disintegrating. 



fixations, notably those containing sublimate, the cells appear to 

 have a coarse fibrillar structure ; but as this is not to be seen either 

 in the fresh cell or after Hermann's, Flemming's, or Hermann's 

 without acetic, it has been regarded here as an artifact similar to that 

 produced in the intestinal cells. ^' 



liver " cell of the 

 He does not, how- 

 ever, figure this ior Oniscus'murarius, on which he used osmic acid. 



•'■•Frenzel (46) sees a fibrillar structure in the 

 marine isopods, relying on picro-sulphuric fixation 



