3 « 
Pharmacological  Notes. 
( Am.  Jour.  Pharm. 
1    January.  1899. 
the  test,  finding  after  adding  the  prescribed  amount  of  normal  acid, 
the  red  color  appears  only  when  over  2  per  cent,  of  carbonate  is 
present ;  in  fact,  when  the  normal  acid  is  omitted,  the  red  color 
appears  only  when  the  amount  of  carbonate  is  over  0-5  per  cent. 
This  data  reckoned  for  the  U.S. P.  test  shows  it  permits  16  per  cent, 
carbonate. 
He  further  investigated  the  quantitative  estimations  of  carbonate 
in  bicarbonate,  finding  unsatisfactory  the  method  based  on  amount 
of  residue  after  red  heat,  absolute  bicarbonate  yielding  63-1  per 
cent,  of  original  quantity,  and  titration  of  this  residue  with  normal 
acid  and  methylorange.  Dietze's  method  was  also  uncertain ;  but 
satisfactory  in  every  respect  was  Ktister's  method,  which  is  as 
follows :  To  a  solution  of  1  gramme  bicarbonate  is  added  20  c.c. 
normal  potassium  hydrate,  part  of  which  is  used  in  converting  the 
bicarbonate  into  the  normal  carbonate.  To  this  is  added  10  per 
cent,  solution  of  barium  chloride  (about  40  c.c),  part  of  which  pre- 
cipitates as  carbonate,  while  another  part  reacts  with  the  excess  of 
KOH ;  an  equivalent  amount  of  barium  hydrate  being  formed. 
This  is  estimated  by  titration  with  normal  acid  and  phenolphtalein, 
when  the  quantity  of  excess  potassium  hydrate,  and  therefrom  the 
amount  of  that  reagent  used  in  converting  the  bicarbonate  into  car- 
bonate can  be  deduced ;  the  factor  of  the  latter  being  0.084  grammes 
bicarbonate  to  each  c.c.  of  normal  alkali  employed. 
In  conclusion,  he  finds  commercial  bicarbonate  usually  contains 
only  1  to  1-5  per  cent  of  normal  carbonate.  H.  V.  A. 
PHARMACOLOGICAL  NOTES. 
THERAPEUTICS  OF  PODOPH YLLIN . 
Dr.  Hector  W.  G.  Mackenzie  and  Dr.  Walter  E.  Dixon  [Edinburgh 
Med.  Jour,  for  November,  vide  New  York  Med.  Jour.,  December 
10th)  conclude  from  their  researches  that  Indian  podophyllin  (ob- 
tained, we  suppose,  from  Podophyllum  Emodi,  Wallich)  is  an 
active  purgative  and  a  useful  therapeutic  agent,  that  it  may  be  sub- 
stituted for  P.  peltatum  ;  but  it  is  important  that  the  physician 
should  know  which  sample  he  is  providing,  as  the  Indian  variety  is 
nearly  twice  as  physiologically  active  as  the  American. 
That  the  active  principles  contained  in  the  crude  resin  are  two 
substances : 
(a)  Crystalline  podophyllotoxin. 
