22 
Polygonum  Hydropiper. 
Am.  Jour.  Pharm. 
Jan.,  1885. 
of  solid  matter.  No  crystalline  principle  was  found,  but  there  was 
obtained  '55  per  cent,  of  gum  and  1*44  per  cent,  of  sugar.  That  por- 
tion of  the  drug  insoluble  in  water  yielded  5'95  per  cent,  of  solid 
matter  to  a  '2  per  cent,  solution  of  potassium  hydrate,  which  was  made 
up  to  1  per  cent,  of  albuminoids  and  some  phlobaphene.  That  which 
remained  from  the  treatment  with  dilute  alkali  gave  to  hydrochloric  acid 
6  per  cent,  of  solid  matter  which  consisted  principally  of  the  salts  found 
in  the  ash.  Only  a  very  small  amount  of  starch  was  found.  On 
bleaching  the  final  residue  Avith  chlorine  water,  drying  and  weighings 
57*45  per  cent,  of  cellulose  was  obtained.  Another  portion  of  the 
original  drug  yielded  10*25  per  cent,  of  moisture,  and  on  incineration, 
7*4  per  cent,  of  ash  of  which  3  per  cent,  was  soluble  in  water,  consist- 
ing of  potassium  and  sodium  salts  ;  the  remainder  proved  to  be  iron,, 
aluminium  and  calcium  with  phosphoric  acid. 
Two  tannin  determinations,  by  the  gelatin  and  alum  process,  gave 
very  close  to  3*46  per  cent.  A  tincture  of  the  drug  was  made  with 
diluted  alcohol,  which  contained  the  pungent  principle,  but  on  concen- 
trating by  distillation  that  peculiar  taste  failed  to  show  itself,  either  in 
the  concentrated  residue  or  in  the  distillate.  The  residue  on  treatment 
with  petroleum  spirit,  benzol  and  chloroform,  yielded  nothing.  From 
these  experiments  we  concluded  that  the  active  principle  is  decomposed 
on  the  slightest  heating,  and  that  the  only  proper  preparation  of  the 
drug  would  be  one  made  without  the  application  of  heat. 
In  American  Journal  of  Pharmacy  for  November,  1871,  Dr» 
C.  J.  Rademaker  claims  to  have  isolated  the  active  principle,  which  he 
named  polygonic  acid.  We  prepared  some  of  this  substance  according 
to  his  method,  by  exhausting  the  drug  with  diluted  alcohol,  evaporat- 
ing and  adding  basic  acetate  of  lead,  by  which  we  obtained  the  yellow 
precipitate.  This,  on  treatment  with  HgS,  yielded  to  the  first  portions 
of  ether  shaken  with  it  a  greenish,  and  to  the  successive  portions  a 
brownish  residue.  All  these  portions  were  acid  to  litmus  paper  and 
gave  the  reactions  stated  by  the  author.  We  also  found  this  residue 
to  give  a  precipitate  with  gelatin,  and  in  many  other  ways  to  resemble 
tannic  as  well  as  gallic  acid ;  the  latter  would  account  for  the  crystal- 
line appearance  of  the  residue.  As  such  treatment  of  the  drug  would 
probably  give  tannic  and  gallic  acids,  we  tried  a  mixture  of  the  two 
by  the  same  reagents  as  were  applied  to  the  so-called  polygonic  acid,, 
and  found  a  remarkable  similarity.  The  conclusion  naturally  follows 
that  polygonic  acid  is  a  mixture  of  impure  tannic  and  gallic  acids,. 
