%&87h9arn  '}      Analysis  of  Rhamnus  Purshiana.  165 
from  July  to  September,  either  earlier  or  later  according  to  the  season, 
and  is  possessed  of  its  best  properties  about  the  latter  part  of  August. 
Grindelia  squarrosa  differs  but  slightly  in  appearance  with  the  Grindelia 
lobusta  j  it  prefers  the  lowlands  and  prairies,  and  grows  very  abundantly 
from  July  to  September. 
W.  C.  Atherden. 
CHEMICAL  and  MICROSCOPICAL  ANALYSIS  of  the  BARK 
of  RHAMNUS  PURSHIANA  (CASCARA  SAGRADA).1 
By  Albert  B.  Prescott,  M.  D.- 
The  examination  embraced  (1)  The  Structure  of  the  Bark  ;  and  (2) 
The  Chemical  Constituents  of  the  Bark, 
(i)  The  Structure  of  the  Bark. 
I.  The  corky  layer  (a).  This  consists  of  the  outer  epidermis  of  dark 
brown  weathered  cells,  then  several  rows  of  cells  filled  with  a  dark  red 
coloring  matter  and  in  the  more  recent  bark,  a  row  or  two  of  cells 
containing  chlorophyll.  The  red  color  (e)  is  soluble  in  ether,  alcohol, 
potassium  hydrate  solution  (with  a  dark  brown  color),  insoluble  in  acetic 
acid. 
II.  The  ?niddle  bark  (b)  is  made  up  of  parenchymatous  cells  which 
are  filled  with  small  starch  grains.  There  are  visible,  also,  in  the 
transverse  section,  several  groups  of  cubical  crystals  (f),  and,  in  the 
longitudinal  section,  groups  of  very  thick- walled  yellow  cells  (k).  These 
cells  (£)  are  not  noticeably  affected  by  the  ordinary  re-agents. 
III.  The  inner  bark  (c)  consists  principally  of  vellow  medullary  rays 
(d),  separated  by  bast  parenchyma  (g),  through  which  are  scattered 
numerous  yellow  bast  fibres  (h).  As  seen  in  longitudinal  section,  these 
fibres  (h)  are  frequently  surrounded  by  small  cubical  crystals  (f):  The 
crystals  (f)  appear  not  to  be  affected  by  hydrochloric  acid. 
Almost  the  entire  inner  bark  (III),  and  parts  of  the  middle  bark  (II) 
are  turned  cherry-red  color  by  contact  with  potassium  hydrate  solution. 
]  The  sample  of  the  bark  examined  was  furnished  me  by  Messrs.  Park,  Davis  Sc 
Co.  I  have  given  no  attention  to  its  identity,  as  bark  of  the  Rhamnus  purshiana. 
However,  its  structure  closely  resembles  that  of  rhamnus  fYangula  bark,  while  having 
-distinct  differences  from  the  latter  (see  Cortex  Frangula?,  in  Hager's  "Pharmaceutische 
Praxis,"  also  "  Pharmacopcea  Germanica  " ). 
'  Reprint  from  "New  Preparations,'1  communicated  by  the  author. 
