AmAp°rn;  S.rm* }     Potassium  Nitrite  in  Potassium  Hydrate.  173 
Lin. ;  namely  a  coloring  matter  called  cuereetagetin,  red  coloring  mat- 
ter, uncrystallizable  sugar,  pectin,  wax,  resin  and  salts. 
Zopatle,  Montagnsea  tomentosa,  De  Cand.,  and  M.  floribunda,  La 
Llave  et  Lejarza;  Composite;  in  the  Mexican  valley,  the  second 
species  also  in  Keal  del  Monte  and  in  Tlalpujahua.  The  first  species 
has  the  stem  cylindrical,  striate  and  with  gray  and  white  spots  un- 
derneath the  tomentam;  the  leaves  13  Cm.  long  and  7  Cm.  broad, 
triangular-oval,  subcordate,  triplinerved  and  toothed.  The  second 
species  has  a  villous-pubescent  stem  and  deltoid-oval  and  subdentate 
leaves.  F.  Altamirauo  found  in  the  plant  albumin,  gum,  fat,  extrac- 
tive, resins,  a  neutral  brown-yellow  bitter  principle,  and  a  peculiar 
acid,  soluble  in  water  and  alcohol,  and  producing  yellow  precipitates 
with  lead  salts.  The  juice  of  the  plant  and  the  decoction  are  popu- 
larly used  for  producing  contraction  of  the  womb. 
Zumaque  venenoso,  Rhus  Toxicodendron  Lin.  The  dose  of  the 
powdered  leaves  is  given  as  being  0  20  to  0*60  gm.  per  day ;  but  the 
dried  leaves  are  stated  to  be  unreliable,  while  the  fresh  ones  are  danger- 
ous ;  the  tincture  prepared  from  the  fresh  leaves  is  to  be  preferred  for 
medical  use. 
THE  PRESENCE  OF  POTASSIUM  NITRITE  IN  THE  PO- 
TASSIUM HYDRATE  OF  COMMERCE.1 
By  Peofessoe  AVyxdham  Dunstax. 
The  object  of  this  paper  is  to  draw  attention  to  a  prevalent,  though 
hitherto  unnoticed,  impurity  in  certain  specimens  of  the  potassium 
hydrate  of  commerce.  In  consequence  of  having  observed  unusual 
reactions  with  a  solution  of  potash  I  was  led  to  make  a  complete  ex- 
amination of  the  specimen  from  which  it  had  been  prepared.  This 
had  been  obtained  from  a  well-known  wholesale  house,  and  was  cast 
in  sticks  having  a  light  green  tint.  The  aqueous  solution  after  being 
acidulated  with  pure  dilute  sulphuric  acid  copiously  liberated  iodine 
from  potassium  iodide.  This  in  itself  is  not  of  course  sufficient  evi- 
dence of  the  presence  of  a  nitrite,  but  that  the  reaction  was  actually 
due  to  this  impurity  was  proved  by  the  effect  on  ferrous  sulphate  and 
by  the  evolution  of  ammonia  when  a  strong  aqueous  solution  was 
boiled  with  metallic  zinc,  as  well  as  by  other  tests  for  nitrous  acid. 
The  quantity  of  potassium  nitrite  present  was  estimated  by  titrating 
1  Eead  at  an  Evening  Meeting  of  the  Pharmaceutical  Society,  Wednesday, 
March  10, 1886. 
