Am .  Jour.  Pbarm.  \ 
January,  1896.  J 
North  American  Conifer ce. 
35 
The  alkannin  test  showed  that  oleoresin  is  not  confined,  by  any 
means,  to  the  secretion  reservoirs,  or  to  the  two  or  three  circles  of 
cells  immediately  surrounding  them,  but  occurs  also  in  many  of  the 
parenchymatous  cells  of  the  cortex  and  bast  layer,  in  the  medullary- 
ray  cells  that  cross  the  xylem,  in  a  few  of  the  tracheids  of  the 
xylem,  and  in  many  of  the  parenchyma  cells  of  the  pith. 
Considering  the  xylem  cylinder  as  a  whole,  however,  it  contains 
far  less  oleoresinous  matter  than  the  tissues  exterior  to  the  cam- 
bium zone. 
Fig.  4,  small  portion  of  cross-section  of  leaf  of  same  species,  magnified  750 
diameters  to  show  stoma;  a,  epidermal  cell;  6,  hypodermal  fibre;  c,  one  of  trie 
mesophyli  cells,  deprived  of  its  granular  contents  by  bleaching  solution;  d,  one 
of  the  guard  cells  of  a  stoma.  The  sections  from  which  Figs.  3  and  4  were 
drawn  had  been  treated  with  Iyabarraque's  solution  to  remove  the  cell  contents, 
and  afterwards  stained. 
A  few  of  the  large  parenchymatous  cells  of  the  cortex  were 
observed  to  contain  crystals.  In  some  instances  a  single  cell  would 
contain  great  numbers  of  them,  but  the  crystals  themselves  were 
not  coherent  or  massed.  No  sphere  crystals,  in  fact,  were  observed. 
As  the  crystals  slowly  disappeared  without  effervescence  when  the 
sections  were  treated  with  hydrochloric  acid,  the  conclusion  was 
that  they  are  composed  of  calcium  oxalate. 
