356 
North  American  Coniferm. 
/Am.  Jour.  Pharm. 
I       July,  1897. 
a  deep  purple,  and  this  coloring  matter  was  bleached  out  with  diffi- 
culty, even  by  Labarraque's  solution.  This  coloring  matter  appeared 
to  be  different  in  character  from  the  reddish-brown  coloring  sub- 
stance foundjn  the  tissues  between  the  bands  of  cork,  for  not  only 
was  the  latter  a  different  shade  of  red,  but  it  bleached  more 
readily. 
7JV 
Fig.  58. 
Fig.  58. — Small  portion  of  longitudinal-tangential  section  of  bark  of  Tsuga 
Mertensiana,  magnified  about  75  diameters,  s,  cluster  of  stone  cells  ;  cr,  crys- 
tals of  calcium  oxalate  ;  m,  m,  medullary  rays  ;  r,  oleo-resin  cell. 
Tests  for  tannin  showed  in  Tsuga  Mertensiana  that  the  white  or 
colorless  younger  portions  of  the  bark  contained  but  little  of  it, 
while  the  older  portions,  particularly  the  dead  sieve  and  parenchyma 
tissues  between  the  bands  of  secondary  cork,  were  observed  to  be 
particularly  rich  in  it. 
Stone  cells  of  large  size,  and  often  quite  irregular,  occurred,  either 
