Wafer  Ash  Bark. 
(Am.  Jour.  Pharm. 
*■     March,  191 8. 
0H  W 
Histology  of  Wafer  Ash  Bark. — Under  the  microscope  the  fol- 
lowing structural  characteristics  may  be  observed,  passing  from 
outer  to  inner  surface  : 
1.  Numerous  layers  of  tangentially  elongated  cork  cells,  the 
walls  of  which  are  more  or  less  lignified. 
