490 
Polygonum  Hydropiper. 
(  Am.  Jour.  Phabbc 
t    Nov.  1, 1871 . 
tated  bj  it,  it  has  been  proposed  to  neutralize  the  water  with  a  few 
drops  of  a  diluted  acid. 
To  eye-waters  only  distilled  water  ought  to  be  taken,  which  it  is 
not  difficult  to  obtain  in  towns  containing  chemical  manufactories. 
An  excellent  substitute  for  distilled  water  has  been  recommended 
by  the  late  Prof.  F.  F.  Mayer,  of  New  York,  in  Am.  J.  Pharm., 
xxxii,  172  :  Put  a  clear  piece  of  ice  in  a  filter,  and  let  it  melt. 
Philadelphia,  Sept.  24.th,  1871. 
THE  ACTIVE  PRINCIPLE  OP  POLYGONUM  HYDROPIPER. 
By  C.  J.  Rademaker,  M.D. 
Having  seen  hydropiper  frequently  used,  both  in  the  form  of  tinc- 
ture and  fluid  extract  in  amenorrhoea  and  other  uterine  disorders,  with 
very  satisfactory  results,  I  was  induced  to  make  a  chemical  exami- 
nation of  this  drug. 
In  order  to  obtain  the  active  principle  or  principles  the  following 
processes  were  resorted  to  : 
Experiment  1st. — Two  pounds  of  the  herb  were  exhausted  with 
diluted  alcohol,  the  alcohol  distilled  off  by  means  of  a  water-bath,  the 
remaining  liquid  was  evaporated  to  about  one-third  of  the  original 
bulk  ;  during  the  evaporation  a  considerable  amount  of  resinous  matter 
was  precipitated,  the  solution  was  filtered  from  the  resinous  precipi- 
tate and  the  filtrate  treated  with  basic  acetate  of  lead,  which  pro- 
duced a  yellow  precipitate. 
The  precipitate  produced  was  collected  on  a  filter  and  washed  with 
distilled  water.  The  precipitated  magma  was  then  suspended  in  dis- 
tilled water  and  treated  with  sulphuretted  hydrogen  ;  the  resulting 
mixture  of  sulphide  of  lead  and  organic  principle  was  treated  with 
ether,  the  ether  separated  from  the  sulphide  of  lead  and  allowed  to 
evaporate  spontaneously. 
The  crystals  thus  formed  were  soluble  in  alcohol,  ether,  chloroform, 
and  slightly  soluble  in  diluted  alcohol,  but  almost  insoluble  in  water  ; 
when  rubbed  with  water  they  become  very  sticky  ;  the  solution  of  the 
crystals  had  an  acid  re-action  with  litmus.  Under  the  microscope 
they  made  a  beautiful  appearance,  resembling  the  crystals  of  uric 
acid  of  human  urine. 
This  acid  may  be  called  polygonic  acid. 
Experiment  2d, — The  filtrate  from  which  the  acid  had  been  re- 
