390 
Aralia  Spinosa, 
Am,  Jour  Pharm. 
Aug.,  1880. 
ARALIA  SPINOSA,  OR  FALSE  PRICKLY  ASH  BARK. 
By  Louis  H.  Holden. 
From  an  Inaugural  Essay. 
The  striking  difference  of  the  physical  characteristics  between  the  . 
barks  of  false  and  true  prickly  ash  (Xanthoxylum)  lies  in  the  appear- 
ance of  the  spmes  and  the  fracture  of  the  bark. 
The  former  presenting  spines  which  are  quite  numerous  compared 
with  the  latter;  they  are  about  one-fourth  inch  in  length,  are  smooth, 
slender  and  tapering  to  a  fine  point ;  their  base  is  round  or  oval,  and 
arranged  in  transverse  rows. 
The  latter  bark  has  few  spines,  scattered  irregularly  ;  they  are 
straight  and  of  the  same  length,  but  two-edged,  with  narrow  linear 
base  of  about  three-fourths  inch  in  length. 
The  false  bark  breaks  with  a  rather  tough  but  nearly  smooth 
fracture. 
The  true  is  brittle,  and  breaks  with  a  short  non-fibrous  fracture. 
In  examining  the  bark  the  following  is  the  result  of  my  analysis: 
Having  reduced  the  drug  to  a  coarse  powder,  it  was  moistened  with 
alcohol  and  packed  in  a  percolator,  exhausted  with  alcohol,  the  alco- 
hol was  removed  by  distillation,  and  the  residue  evaporated  to  a  solid 
extract.  The  extract  was  mixed  with  alcohol  to  the  consistency  of 
syrup,  then  treated  with  benzin,  which  removed  the  fatty  matter  ;  this 
fat  is  of  a  dark  green  color,  which  is  probably  due  to  chlorophyll.  The 
residue  was  then  treated  with  ether  repeatedly,  until  the  portion  insol- 
uble in  ether,  after  being  dissolved  in  water,  would  not  answer  the 
tests  for  tannin. 
On  examination,  I  find  ether  has  removed  from  the  extract  all  of 
the  tannin  and  resin.  Evaporating  the  etherial  solution  to  dryness  and 
washing  the  residue  with  water,  the  tannin  becomes  separated  from 
the  resin. 
The  tannin  is  precipitated  from  aqueous  solution  by  acetate  of  lead  ; 
it  gives  an  emerald-green  color  with  salts  of  iron  ;  with  caustic  potash 
it  turns  ruby-red  ;  the  latter  color,  when  acted  upon  by  oxalic  acid,  is 
destroyed.  The  tannin  coagulates  albumen  ;  it  is  an  astringent,  solu- 
ble in  ether,  alcohol  and  water.  The  alcoholic  extract  cannot  be 
detannated  with  oxide  of  lead,  which  the  following  process  will  prove. 
The  alcoholic  extract  was  mixed  with  water  ;  on  adding  to  this  oxide 
of  lead,  heating,  allowing  to  stand  for  several  days,  then  evaporating 
