AmoTctnyiSarm'}        Corky  Spines  of  Zanthoxylum.  525 
dryness,  dried  at  ioo°  C.  and  weighed.  The  published  statements 
that  the  drug  contains  from  3-9-5-0  percent,  caffeine  (due  to  faulty 
assays)  should  be  reduced  according  to  Thorns'  assays  to  2-6-3-0 
per  cent.  Prof.  E.  Schar  sometime  ago  announced  that  from  the 
acid  solution  of  guarana  ether  extracted  a  crystalline  substance 
behaving  like  morphine  in  some  of  its  reactions  ;  this  same  crystal- 
line substance  Thorns  found  to  be  present  in  the  seeds  and  therefore 
to  be  a  characteristic  constituent  of  these  two  drugs. — Pkarm. 
Ce'niralhalle,  1892,  431. 
THE  CONICAL  CORKY  SPINES  OF  ZANTHOXYLUM. 
The  "  Annals  of  Botany  "  for  July  contains  an  interesting  paper 
by  Mr.  C.  A.  Barber,  B.A.  (Superintendent  of  the  Agricultural 
Department  of  the  Leeward  Islands),  on  the  corky  spines  of  Zan- 
thoxylum. The  author  traces  the  development  of  the  corky  spines 
of  Z.  alatum,  as  observed  in  fresh  material  supplied  by  the  authori- 
ties at  Kew.  The  corky  cone  appears  to  rise  first  as  a  sort  of  cush- 
ion beneath  the  thorn.  In  the  earliest  stage  of  its  growth  it  is 
assisted  by  a  lysigenous  gland,  which  is  found  at  its  base.  The 
tissue  of  this  gland  is  differentiated  by  the  formation  of  a  small  area 
of  cells  with  granular  contents,  around  which  the  neighboring  cells 
become  arranged  concentrically,  and  the  number  of  cells  between 
the  vascular  ring  and  the  epidermis  becomes  increased.  In  a  more 
advanced  stage,  the  cells  on  each  side  of  the  gland  become  collen- 
chymatous,  and  the  thorn  becomes  prominent,  its  cells  elongating 
in  the  direction  of  its  length.  The  cells  outside  the  collenchyma 
then  divide  and  form  a  meristematic  layer  at  the  base  of  the  thorn, 
the  cells  nearer  its  apex  becoming  rapidly  elongated,  pitted  and 
thick-walled.  The  change  takes  place  more  rapidly  at  the  surface 
of  the  thorn,  so  that  a  hard  tissue  is  formed  around  a  softer  core. 
In  the  autumn  the  meristematic  cells  become  sharply  marked  off 
from  the  underlying  cells  of  the  cortex,  and  are  much  shorter  and 
more  closely  packed  than  before,  assuming  and  retaining  a  brick- 
shaped  character,  rapidly  taking  the  appearance  of  corky  tissue,  and 
exhibiting  rings  of  growth,  similar  in  nature  and  appearance  to  the 
rings  of  growth  in  the  stem  of  Pinus.  By  the  rapid  increase  of 
growth  of  the  lower  part  of  the  thorn,  after  the  capacity  for  growth 
in  the  epidermal  cells  has  diminished,  the  tissues  around  the  base  of 
the  thorn  are  ruptured  by  the  tension,  and  the  corky  cushion  of  the 
