138 
North  American  Coniferce. 
<  Am.  Jour.  Pharm. 
t      March,  1896. 
ish,  and  finally  the  walls  break  down,  leaving  a  cavity  or  intercellular 
space  containing  the  oleoresin.  In  the  meantime,  cells  immediately 
bounding  this  space  are  gradually  undergoing  similar  changes,  and 
so  on,  as  long  as  the  secretion  reservoir  continues  to  grow.  So,  if 
any  well- developed  secretion  reservoir,  with  the  surrounding  cells, 
be  examined,  there  will  be  found  :  (i)  a  central  space  filled  with 
oleoresin ;  (2)  an  area  of  cells  immediately  surrounding  this,  which 
contain  much  oleoresin,  and  little  tannin  and  protoplasm ;  and  (3) 
still  farther  exterior,  a 'layer  of  very  granular  cells,  rich  in  protoplasm 
and  tannin,  but  containing  very  little  volatile  oil  or  resin.  In  Pinus 
palustris,  a  species  especially  rich  in  oleoresin,  it  is  also  clearly 
seen  that  the  older  medullary  ray  cells  of  the  wood  are  filled  with 
oleoresin,  but  contain  but  little  tannin,  while  the  reverse  is  the  case 
with  the  younger  medullary  ray  cells.  There  is  no  denying  the  fact 
that,  as  the  resin  increases,  the  tannin  diminishes,  whatever  the  con- 
clusion we  may  draw  from  the  circumstance. 
The  view  that  tannic  matters  are  derived  from  starch  apparently 
obtains  no  support  from  these  observations  on  the  pines.  A  very 
little  fine-grained  starch  was  found  in  the  stems  of  the  pines  investi- 
gated ;  it  was  never  abundant,  while  in  the  roots  it  was  usually 
present  in  considerable  quantity.  On  the  other  hand,  as  respects 
the  tannin  of  the  different  species,  very  little  difference  was  observed 
between  the  roots  and  stems,  either  as  to  the  quantity  or  as  to  the 
distribution  of  the  tannin.  No  indication  whatever  was  found  that 
as  starch  decreases  tannin  increases,  or  of  any  quantitative  relation 
between  the  two  substances.  The  facts  do,  however,  show  an  inti- 
mate relation  between  the  tannin  and  the  protoplasm.  It  is  abun- 
dant in  all  parts  of  the  protoplasm,  even  in  the  nucleus,  though  it 
does  not  appear  to  exist,  normally  at  least,  except  in  very  minute 
quantity,  in  the  cell  wall.  After  the  death  of  the  tissues,  however, 
it  rapidly  diffuses  into  the  cell  walls.  Tannin  was  found  even  in  the 
protoplasm  of  meristem  cells,  though  apparently  in  less  abundance 
than  in  many  of  the  more  mature  cells.  In  the  living  cell  it  seems 
to  be  most  abundant  in  the  ectoplasm.  While  this  does  not  posi- 
tively disprove  that  tannin  is  derived  from  a  carbohydrate,  the  proba- 
bility is  at  least  suggested  that  it  is  derived  from  the  breaking  down 
of  the  proteids  during  the  processes  of  cell  growth.  The  process  is 
probably  complex,  but  no  guess  is  ventured  as  to  what  the  various 
chemical  stages  of  the  process  are. 
