Am.  Jour.  Pharm. ) 
May,  1881.  / 
Quebracho  Bark, 
243 
The  bark  in  question  was  soon  recognized  as  belonging  to  the  genus 
•Croton  (Euphorbiacese)  by  Pohl,  and  was  afterw^ards  identified  by 
Hansen  a  copalchi  bark,  which  was  long  known  in  the  drug  market, 
although  now  obsolete  in  pharmacy;  it  belongs  to  the  group  of  cas- 
carilla  barks  and  is  derived  from  the  Mexican  Croton  pseudochina, 
■Schl.  (Croton  niveus,  Jacq.).  As  is  known,  the  copalchi  bark  agrees 
with  this  false  quebracho  by  occurring  in  tubular  pieces  several 
inches  long,  provided  with  a  grayish-white  powdery  periderm,  and 
varies  in  thickness  from  J  to  2  lines.  The  cross  section  of  the  bark 
-shows  with  the  lens  a  structure  entirely  different  from  the  aspidosperma 
bark,  i.  e.,  a  homogenous  yellowish-white  outer  bark,  and  a  brown  bast 
portion,  which,  by  means  of  the  small  bast  bundles  becoming  pointed 
towards  the  periphery  assumes  a  flame-like  appearance.  Moreover, 
the  croton  bark  possesses  a  spicy  odor  and  taste,  which  is  not  present 
in  true  quebracho.  Another  bark  of  undetermined  botanical  derivation 
consists  of  dark-brown  pieces  with  a  grayish  or  gray-brown  cork 
layer,  and  shows  many  furrows  on  the  inner  side,  without,  however, 
possessing  a  similarity  with  aspidosperma  bark.  The  same  may  be 
said  of  a  bark  of  unknown  botanical  derivation,  which  as  "Cortex 
Quebracho  verus"  has  been  sold  at  a  high  price,  and  has  been  found 
by  Hansen  to  differ  from  all  previous  quebracho  varieties.  This  bark, 
which  is  also  distinguishable  from  the  aspidosperma  by  a  microscopical 
examination,  consists  of  pieces  from  1  to  IJ  inch  in  thickness,  of  a 
brown  color  and  firm  consistence,  characterized  by  numerous  light- 
colored  cork  bands  on  a  cross  section,  and  with  a  slightly  developed 
inner  bark.  It  appears  to  contain  a  large  amount  of  tannin,  but  does 
not  possess  the  remarkable  bitterness  of  the  genuine  quebracho  bark. 
Finally,  the  bark  of  the  Q.  Colorado  tree  appears  occasionally  to  have 
taken  the  place  of  the  "  Q.  bianco'^  bark,  although  it  can  hardly  be  con- 
found with  the  true  quebracho. 
The  Q.  Colorado  bark  is  of  a  brown  or  dark-brown  color  on  the 
exterior  and  possesses  frequently  a  covering  of  lichens.  The  cross 
section  is  light-brown  and  shows  concentric  darker  cork  bands,  as  also 
light  radially  extending  lines,  which  prove  to  be  the  medullary  rays. 
Between  these  latter  uniformly  arranged  groups  of  sclerenchyma  fibres 
are  situated,  which  groups,  several  in  number  and  standing  behind 
each  other,  impart  to  the  bark  a  checkered  appearance.  Although 
these  fibres  show  a  structure  similar  to  the  crystal-covered  fibres  of 
the  aspidosperma  bark,  they  are,  however,  considerably  smaller  and  are 
