286        Pharmaceutical  Notes  from  Purdue  University.  {Am/u0nUe"-i^arm- 
The  oleate  of  arsenic  is  most  likely  only  a  name  for  a  solution  of 
slight  traces  of  arsenic  in  soap,  as  I  haye  been  unable  to  make  an  oleate 
by  the  different  methods  published. 
Oleate  of  veratrine  is  the  only  other  officinal  oleate,  and  it  as  well  as 
the  other  oleates  of  alkaloids,  are  easily  made  by  simply  dissolying  the 
alkaloids  in  the  acid. 
XI.    Potassii  Bit  art  r  as. 
Specimens  of  bitartrate  of  potassium  procured  from  twelve  drug- 
gists were  submitted  for  examination  (under  careful  oversight)  to 
members  of  the  junior  class. 
While  the  limits  of  impurity  are  fixed  at  a  " turbidity"  caused  by 
barium  and  silver  salts,  few  specimens  will  meet  a  rigid  interpretation 
of  the  requirements.  Xot  more  than  one  or  two  of  the  twelve  sam- 
ples, however,  seemed  to  have  enough  sulphate  to  be  called  an  actual 
impurity,  while  only  one  contained  a  questionable  amount  of  chloride. 
The  tests  for  calcium  were  made  in  Messier  tubes,  resting  upon  a  fine 
dotted  line  on  white  paper;  the  fluid  was  considered  "cloudy"  when 
the  dots  were  obscured,  and  "turbid"  when  printed  letters  were  in- 
distinguishable. With  this  interpretation  of  the  pharmacopceial  test, 
seven  samples  were  pronounced  good,  one  was  fair,  and  four  were 
questionable.    Two  samples  gave  unmistakable  reactions  for  starch. 
A  thirteenth  sample  (expressly  sold  as  a  cheaper  grade)  had  a  de- 
cided excess  of  sulphate  and  a  questionable  amount  of  calcium. 
Two  samples  were  also  procured  from  a  manufacturer,  who  offers 
"pure  cream  of  tartar,"  in  small  lots,  at  45  cents  per  pound,  and 
various  sophistications,  at  prices  to  suit  the  demand  of  grocers,  down 
to  14  cents.  One  of  these  samples  was  unobjectionable,  except  in 
containing  more  than  the  average  amount  of  sulphate  and  chloride ; 
while  the  other,  on  treatment  with  water,  leaves  an  insoluble  residue 
of  calcium  sulphate  (amounting  to  6  2 '4  per  cent,  after  ignition),  and 
the  aqueous  extract  from  a  weighed  quantity  neutralized  only  one- 
sixth  as  much  alkali  as  an  equal  weight  of  bitartrate  of  potassium. 
See  further  details  in  Indiana  Pharmacist,  iv,  300  (Feb.  1886). 
XII.    Potassii  JSTitras. 
A  careful  examination  shows  that  when  genuine  saltpetre  (nitrate  of 
potassium)  is  offered  for  sale,  it  is  practically  free  from  all  impurities, 
except  traces  of  chloride,  as  indicated  by  numbers  1  to  8.    There  are, 
