388 
Viburnum  Prunifolium. 
f  Am.  Jour.  Pliarin. 
\      August,  1S95. 
corky  layer  easily  removed  from  the  green  layer ;  inner  surface  whitish, 
smooth;  fracture  short ;  inodorous;  somewhat  astringent  and  bitter." 
Among  the  problems  presented  to  Research  Committee  C  by  its 
chairman,  Dr.  H.  H.  Rusby,  is  one  which  relates  to  the  question  of 
discrimination  of  these  two  barks,  particularly  in  the  crushed  or 
powdered  condition,  and  one  relating  to  the  distinction  between  the 
bark  of  the  root  and  bark  of  the  stem  of  Viburnum  prunifolium. 
Entering  upon  the  investigation,  I  have  formulated  the  problem  as 
follows : 
(1)  What  are  the  distinguishing  characteristics  which  will  identify 
the  bark  of  the  stem  and  the  bark  of  the  root  of  Viburnum  pruni- 
folium ? 
(2)  How  can  one  distinguish  between  the  bark  of  Viburnum 
prunifolium  and  V.  opulus  ? 
(3)  What  are  the  differential  characteristics  of  these  barks  which 
will  enable  one  to  distinguish  between  them  in  the  crushed  condi- 
tion or  in  the  state  of  powder  ? 
Before  seriously  taking  up  the  third  question,  it  is  necessary  to 
have  clearly  before  one  the  gross  characteristics  of  these  barks,  and 
to  understand  the  relation  between  them  structurally  as  well.  At 
the  same  time,  it  is  essential  that  such  a  knowledge  of  the  constitu- 
ents be  had  as  shall  enable  one  to  compare  them  pharmaceutically. 
It  is  the  object  of  this  paper  to  lay  before  those  who  desire  to 
contribute  to  the  work  a  statement  of  what  has  been  done  thus  far 
in  answering  the  first  and  second  questions.  I  am  gratified  to  state 
that  there  are  those,  even  outside  of  the  committee,  who  have  inter- 
ested themselves  in  the  work,  and  who  desire  such  a  statement.  It 
is  this  that  has  suggested  this  paper. 
For  authentic  specimens  for  the  investigation  I  am  indebted  to 
Dr.  H,  H.  Rusby.    These  were  as  follows  : 
NAME  OF  SPECIMEN  AND  PHYSICAL  CHARACTERISTICS. 
I.  Viburnum  opulus. —  Trunk  bark,  commercial  specimen  from 
Parke,  Davis  &  Co.  Curved  pieces  from  6  to  10  inches  (150  to 
250  mm.)  in  length,  and  about  ^  inch  (2  mm.)  in  thick- 
ness, the  inner  surface  usually  with  strips  of  the  white  wood  adher- 
ing. The  baric  consists  of  three  layers,  the  periderm,  a  green  chlo- 
rophyll layer,  and  a  yellowish  or  brownish-yellow  inner  bark.  The 
periderm  is  nearly  smooth,  especially  on  the  younger  bark,  greenish 
or  greenish-gray,  marked  with  greenish  and  whitish  patches,  and 
