♦ 
A.m.  Jour.  Pharm.  1 
May,  1891.  J 
Phlox  Carolina. 
227 
The  transverse  section  of  a  light  colored,  well-developed  root 
shows  a  small  central  woody  column  enclosed  within  an  endodermis 
and  surrounded  by  a  comparatively  large  cortex.  In  the  latter  por- 
tion of  the  section  the  eye  is  at  once  arrested  by  numerous  stone- 
cells,  and  also  by  the  presence  in  a  number  of  cells  of  an  apparently 
granular  mass  more  or  less  completely  filling  them.  Here  and  there 
a  small  fragment  of  red  coloring  matter  (phloxol  ?)  is  visible. 
A  tangential  section  -shows  the  stone-cells  to  be  of  remarka- 
ble length.  It  also  discloses  the  nature  of  the  granular  masses  ; 
they  are  large  and  well-formed  cystoliths.  These  are  usually 
more  or  less  cylindrical  in  shape,  not  acutely  pointed,  as  is  some- 
times the  case. 
On  treating  a  section  with  dilute  hydrochloric  acid,  the  calcium 
carbonate,  of  which  they  are  principally  composed,  dissolves  with 
effervescence,  leaving  the  cellulose  skeleton  undissolved.  The  pres- 
ence of  the  stone-cells  and  cystoliths  renders  the  section  both  char- 
acteristic and  interesting. 
Neither  of  them  are  confined  to  the  root,  but  are  to  be  found  as 
well  in  the  parenchymatous  tissue  of  the  rhizome  and  aerial  stem. 
Here  the  cystolith,  varying  in  shape  with  the  cell  which  it  occupies, 
is  frequently  nearly  cubical,  whilst  the  stone-cells  assume  approxi- 
mately similar  dimensions. 
A  few  years  ago  cystoliths  were  thought  to  be  confined  almost 
