Fig. 3. The micrograph shows a small field in the basal region of a pancreatic exocrine 

 cell which was damaged (cut open) during the trimming of the tissue block before fixation. 



A comparison with figure 2 indicates that in the damaged cell the profiles of the endo- 

 plasmic reticulum have distended cavities and are predominantly circular. In three dimen- 

 sions they correspond to spherical and oval vesicles. An enspherulation of this type is 

 usually accompanied by a breaking-down of the system into a collection of isolated vesicles. 

 Note that the vesicles are still aligned in more or less parallel rows. 



The limiting membrane of the vesicles and its attached particles appear in normal section 

 at n, and in oblique section at o. In this case there are few free particles left in the 

 cytoplasmic matrix. 



Fixation and embedding as for the specimen in figure 2. 



Magnification: 50,000. 



