386 
North  American  Conifer ce. 
Am.  Jour.  Pharm. 
July,  1896. 
from  13^  to  2^  inches,  and  the  thickness  from  S/%  inch  to  ^  inch. 
The  color  of  the  cones  is  light  brown. 
MICROSCOPICAL  STRUCTURE. 
A  cross-section  of  a  twig  of  two  years'  growth  showed  the  follow- 
ing structure :  The  thick- walled  epidermal  cells  were  supported  by 
two  or  three  layers  of  thick-walled  fibres.  Beneath  this  was  a 
large-celled,  thin-walled  parenchyma,  consisting  of  several  layers  of 
cells.  This  was  succeeded  internally  by  bands  of  periderm,  com- 
posed in  part  of  stone  cells,  and  in  part  of  thin-walled  cells  contain- 
ing much  tannin.  Interior  to  these  was  a  copious  parenchyma,  con- 
taining numerous  scattered  tannin  cells  and  some  secretion  reser- 
voirs for  oleoresin.  The  bast  layer  contained  no  lignified  fibres, 
and  there  were  numerous  large  secretion  cells  containing  tannin  ; 
these  were  arranged  in  tangential  rows.  The  medullary  rays  of  this 
layer  were  wavy,  and  its  cells  were  also  rich  in  tannin.  The  xylem 
closely  resembled  that  of  the  pines,  except  that  the  secretion  reser- 
voirs were  rather  less  numerous  and  smaller.  A  longitudinal- 
tangential  section  showed  medullary  rays,  longer  and  more  numer- 
ous than  those  of  the  pines.  In  the  bark  were  observed  scattered 
clusters  of  stone  cells,  and  some  cells  containing  crystals  of  calcium 
oxalate. 
The  leaves  of  Picea  alba  are  of  small  size,  from  y2  to  ^ 
inch  long  and  about  inch  thick.  They  are  quadrangular- 
prismatic,  sharp-pointed,  and  have  on  each  of  the  four  sides 
two  or  three  more  or  less  interrupted  rows  of  stomata.  The 
secretion  reservoirs  at  the  lateral  angles  are  of  small  size.  The 
epidermis  has  the  outer  walls  of  its  cells  thick  and  strongly  cutin- 
ized ;  the  lateral  and  inner  ones  much  less  thickened.  The  hypo- 
derma  is  composed  of  one  layer  of  cells,  some  of  them  with  thin 
walls,  others  with  thick  ones.  The  mesophyll  is  composed  of  wavy- 
walled  cells.  The  fibro-vascular  bundle  is  thin  and  has,  at  the 
upper  margin  of  the  phloem,  a  few  thick-walled  fibres.  The 
transfusion  tissue  is  few-layered,  and  the  endodermis  distinct  and 
composed  of  cells  having  their  radial  walls  somewhat  thickened. 
(To  be  continued.} 
Dr.  A.  L.  Metz,  who  was  appointed  temporary  Professor  of  Chemistry  to 
fill  the  vacancy  in  the  Medical  Department  of  Tulane  University,  New  Orleans, 
caused  by  the  death  of  Professor  Joseph  Jones,  has  been  elected  permanently 
to  the  chair. — Medical  News. 
