Information Storage in Nerve Cells 221 



1 . ^ 



. i" ^' 



Fig. 24. Sections Lhruugh ilic region ul ilit- uiinur lucus. Note the collection 

 of densely stained cells to the right of the photomicrograph compared with the 

 characteristic staining of normal cortex to the left. Methyl green pyronin stain. 



Magnification x75 (39). 



higher power photomicrograph (Fig. 25) illustrates the pene- 

 tration of the pyronin-positive material into the dendrite and 

 also indicates the wedgelike distribution of the stained cell system. 

 Pigmented cells extend throughout the depth of the cortex. At 

 still higher magnification the extent of penetration into the dendrite 

 is clearer (Fig. 26) and one may observe a concentration of the 

 pyronin-positive material in a dense layer along the inner surface 

 of the cell membrane. The altered tinctorial properties of these 

 cells were abolished by pre-treatment of the slide with ribonuclease 

 and were unaffected by similar treatment with deoxyribonuclease 

 and other enzymes. Although the histochemical picture was some- 

 what obscured by surgical artifacts the cells in the isolated mirror 

 focus exhibited the same pyronin-dense-pattern as had the intact 

 secondary region. Further controls may be found in the original 

 report (39). 



