274  Content  of  Ash  of  Certain  Drugs.   {Am,AJp°r"1r'  Ip9hIlrm' 
with  the  unknown  solution  with  regard  to  acidity  and  general  ion 
concentration. 
In  cases  of  the  first  order  of  Manganese  content,  10  Gm.  samples 
of  the  well-ground  materials  were  ashed  in  platinum  in  a  muffle  and 
20  Cc.  of  pure  concentrated  sulphuric  acid  was  added.  The  sample 
was  then  heated  till  the  acid  fumed  freely  in  order  to  remove  chlo- 
rides. It  was  then  cooled  and  diluted  with  distilled  water,  washed 
out  into  a  500  Cc.  beaker  and  diluted  to  at  least  300  Cc.  To  this 
solution  was  added  one  Cc.  of  a  silver  nitrate  solution  (5  Gm.  in  100 
Cc.)  and  the  whole  warmed  to  about  8o°.  Approximately  one  Gm. 
of  ammonium  persulphate  was  gradually  stirred  into  this  solution, 
which  was  then  heated  on  the  steam  bath  as  long  as  the  color  of 
the  permanganate  deepened.  By  check  analyses  the  reaction  was 
found  generally  to  be  complete  at  the  end  of  30  minutes.  The  so- 
lution was,  however,  heated  45  minutes  and  allowed  to  cool.  When 
cold  it  was  rapidly  titrated  with  sodium  arsenite  solution  which  had 
been  standardized  against  known  amounts  of  permanganate  devel- 
oped in  the  same  way.  Unless  the  dilution  is  sufficient  a  brown 
hydrated  form  of  manganese  will  separate  out  after  the  addition  of 
the  ammonium  persulphate.  Where  the  percentage  of  manganese 
is  as  high  as  0.06  a  volume  of  500  Cc.  is  necessary  when  working 
on  a  10  G.  sample. 
In  cases  where  the  manganese  was  of  a  lower  order  than  0.01 
per  cent,  the  color  was  developed  as  above  from  a  10  Gm:  sample  in  a 
200  Cc.  volumetric  flask  and  compared  by  means  of  a  colorimeter 
with  standard  solutions  of  permanganate. 
Our  thanks  are  due  to  Dr.  J.  M.  Francis,  of  the  Parke  Davis  Co., 
Detroit,  Mich.,  for  kindly  supplying  us  with  genuine  samples  of 
some  of  the  above  materials. 
Summary. —  (1)  The  manganese  content  of  certain  laxative 
drugs  has  been  measured  along  with  allied  species  of  plants. 
(2)  It  has  been  found  that  for  the  family  Rhamnacese  the  man- 
ganese is  extracted  in  water  proportionally  to  its  total  amount  in 
the  bark. 
(3)  A  practical  use  of  this  determination  is  suggested  leading  to 
the  establishment  of  a  "  Manganese  Number  "  for  extracts  of  these 
drugs. 
