446 
ON  RESINS  OP  JALAP  AND  SCAMMONIUM. 
After  having  satisfied  myself  that  bromides  and  chlorides  are 
not  decomposed  by  hyponitric  acid,  and  that  their  presence  does 
not  hinder  its  reaction  with  iodides,  a  mixed  solution  of  iodide 
of  potassium,  bromide  and  chloride  of  sodium,  was  first  treated 
with  hyponitric  acid  and  shaken  with  chloroform.  When,  after 
standing  for  some  time,  the  colored  chloroform  solution  had  sepa- 
rated, it  was  carefully  removed,  washed  with  water,  and  mixed 
with  a  solution  of  potash  of  known  value  until  decolorized.  The 
remaining  saline  solution  was  then  treated  with  a  mixture  of 
nitric  and  sulphuric  acids,  shaken  with  chloroform  to  separate 
the  bromine,  and  the  chlorine  then  estimated  by  precipitation 
with  a  nitrate  of  silver  solution  of  known  value.  The  experi- 
ments were  made  with  0-050  or  0-100  grm.  iodide  of  potassium, 
the  same  quantity  of  bromide,  and  1-000,  1-500  and  2-000  grm. 
of  chloride  of  sodium ;  the  results  were  as  exact  as  could  be  ex- 
pected. The  difference  in  the  results  did  not  amount  on  the 
average  to  more  than  0-006  for  bromide  and  iodide  of  potassium, 
and  for  chloride  of  sodium  0-002  grm. 
The  method  proposed  by  Moride  for  the  separation  of  these 
elements  by  means  of  benzin,  is  less  advantageous  for  their  quan- 
titative estimation. 
Penny's  method  of  estimating  iodine — by  means  of  the  reac- 
tion between  solubles  iodides,  hydrochloric  acid,  and  chromate  of 
potash : 
3  KI+KO,  2  Cr  03+7  H  Cl=I3+4  K  Cl+Cr3  Cl3+7  HO. 
is  not  to  be  recommended  for  general  adoption,  as  it  cannot  be 
applied  directly  to  the  valuation  of  commercial  iodine  or  kelp, 
for  in  the  former  case  the  iodine  must  be  first  converted  into 
iodide  of  zinc,  and  in  the  latter  the  sulphurets,  sulphites,  hypo- 
sulphites and  sulphocyanides,  must  be  previously  separated. — 
London  Pharm.  Journ.,  from  Jahrbuch  fur  praktisehe  Phar- 
macie. 
A  SIMPLE  METHOD  TO  PROVE  THE  GENUINENESS  OF  THE 
KESINS  OF  JALAP  AND  SCAMMONIUM. 
By  A.  Buchner. 
The  principal  constituent  part  of  the  resin  of  jalap,  rhodeore- 
tin,  which  is  insoluble  in  ether,  according  to  the  experiments  of 
