Am.  Jour.  Pharm. 
April,  1889. 
Medicinal  Catechu. 
165 
The  reaction  taking  place  in  the  above  is  most  likely  as  follows  : 
(1)  BiON03.H20  +  2  HN03  =  Bi  3  N03  +  2  H2G. 
(2)  3  (Bi  3  N03)  +  3  KI  =  Bil8  +  2  (Bi  3  N03)  +  3  KN03. 
(3)  Bil8  +  2  (Bi  3  N03)  +  3  H20  =  3  BiOI  +  6  HN03. 
(heated — ) 
The  mode  of  analysis  which  was  pursued  in  these  experiments, 
is  as  follows  : — 
For  estimation  of  Iodine. — Place  0*5  gm.  BiOI  in  a  flask  with  a 
few  pieces  of  test  zinc,  cover  with  water,  and  mix  thoroughly,  then 
add  sufficient  H2S04  to  evolve  hydrogen  slowly,  at  the  same  time 
decomposing  the  BiOI.  Thus  if  combines  with  J  to  form  hydriodic 
acid,  while  ZnS04  is  formed  and  Bi  is  precipitated  in  black  flocculent 
masses.  This  reaction  is  completed  in  two  or  three  hours.  Neutral- 
ize the  resulting  mixture  carefully  with  KHO,  add  a  few  drops  of 
solution  K2  Cr04  as  an  indicator;  titrate  with  one-tenth  normal  solu- 
tion of  AgN03  until  a  red  precipitate  begins  to  form.  The  percentage 
of  iodine  is  then  calculated  as  by  U.  S.  P.  process. 
For  estimation  of  Bismuth. — Dissolve  0*5  gm.  BiOI  in  a  small 
quantity  of  nitric  acid,  dilute  with  water,  boil  until  all  iodine  has 
been  vaporized  and  all  odor  of  HlSTOg  has  disappeared  ;  add  to  this 
KHO,  until  a  precipitate  is  formed  which  does  not  redissolve  on 
shaking.  Collect  on  a  plain  filter,  wash  well,  ignite  and  weigh  as 
Bi203. 
MEDICINAL  CATECHU. 
By  Edwin  Stanton  Reider,  Ph.G. 
From  an  Inaugural  Essay. 
The  examination  and  estimations  presented  in  this  essay  were 
undertaken  with  the  view  of  ascertaining  the  medicinal  worth  of 
catechu  as  it  is  found  in  the  drug  market.  Eighteen  samples  were 
obtained  from  various  sources  and  the  results  gotten  from  these  were 
considered  to  be  a  fair  indication  of  the  condition  of  the  drug  in 
general. 
Samples  1  to  6  were  in  powdered  state,  the  remainder  were  in 
mass.  Nos.  1,  2,  7  and  8  were  obtained  from  Baltimore,  Md.,  direct 
from  the  jobbers.  Nos.  11,  15  and  16  from  the  same  city,  but  re- 
ceived through  retailers.  Nos.  5  and  9  were  procured  from  a  whole- 
sale drug-house  in  New  York  City.    The  remaining  samples  were 
