Am  Jour.  Phani..  i 
Nov.,  1880  ( 
Cinchonas  of  U.  S.  Commerce. 
53  J 
under  cinchonas.  Berg's  stone-cells  and  the  resin-cells  of  the  Dispens- 
atory are  the  same,  and  therefore,  2d,  that  the  resin-cells "  must  be 
only  the  thicker  walled. 
The  crystal  cells,  so  often  spoken  of,  are  of  little  aid  in  classification. 
Th  ir  contents  are  grmular,  and  slightly  crystalline  in  appearance. 
inchona  succirubra.    x  40.  Cinchona  micrantha.  x 
(.Older  bark.) 
3d.  The  corky  layer,  of  varying  thickness  (periderm).  Sometimes 
this  penetrates  into  the  middle  or  even  inner  bark,  forcing  off  the  tissue 
external  to  it  as  bark-scales,  itself  forming  rhytidoma°  (periderm  of 
Weddell,  Borke  of  the  Germans).  This  secondary  cork,  or  the  effects 
of  its  growth,  is  always  observable  in  older  C.  calisaya. 
