Am.  Jour.  Pharm.  ) 
August,  1913.  j 
A  Note  on  Aqua  Camphor®. 
379 
mining  the  zinc  in  the  residue  volumetrically,  gravimetrically,  or 
electrolytically  and  calculating  to  oxide. 
There  does  not  appear  to  be  any  reason  why  the  method  can- 
not be  employed  with  equally  good  results  for  the  analysis  of  Zinc 
Stearate  Ointment.  In  this  case  the  amount  of  stearate  present 
could  easily,  be  calculated  from  the  residue,  which  is  zinc  oxide. 
The  method,  in  addition  to  being  rapid,  is  accurate  and  easily 
applied. 
A  NOTE  ON  AQUA  CAMPHOR^.1 
By  John  K.  Thum,  PhG.,  German  Hospital,  Philadelphia. 
Those  of  us  who  have  occasion  to  make  considerable  quantities 
of  camphor  water  are  conversant  with  the  shortcomings  of  the 
present  official  method.  The  method  consists  in  dissolving  8  grams 
of  camphor  in  8  cubic  centimetres  of  alcohol,  triturating  the  solu- 
tion with  15  grams  of  purified  talc,  allowing  the  greater  part  of 
the  alcohol  to  evaporate  spontaneously,  continuing  the  trituration 
with  distilled  water  to  make  one  litre  and  filtering  through  a  wetted 
filter. 
By  this  method,  after  a  few  days,  the  preparation  begins  to  get 
cloudy  and  shows  unmistakable  signs  of  fungus-like  growth.  Al- 
though the  statement  appears  in  some  of  the  literature  relating  to 
camphor  that  it  is  soluble  in  water  to  the  extent  of  two  grains  to 
a  fluidounce,  it  is  not  true  and  is  readily  disproven ;  if  it  were  true 
fungi  would  not  appear,  as  camphor  is  somewhat  antiseptic. 
The  U.  S.  P.  states  that  camphor  is  "  sparingly  soluble "  in 
water,  and,  as  practice  bears  out  this  statement,  it  follows  that  in 
the  present  U.  S.  P.  method  for  making  the  water  practically  all 
of  the  camphor  remains  on  the  filter  with  the  talc.  It  seems  to  the 
writer  that  the  combination  of  alcohol  and  camphor  causes  some  of 
the  talc  to  go  into  solution  and  as  the  alcohol,  or  the  greater  part 
of  it,  gradually  evaporates  after  the  lapse  of  time,  the  talc  is 
thrown  out  of  solution.  That  camphor  water  prepared  by  this 
method  shows  up  clear  when  first  made  is  true,  but  only  for  a  short 
time,  then,  as  stated  before,  cloudiness  appears  which  necessitates 
frequent  nitration.    To  a  busy  pharmacist  this  is  an  annoyance. 
1  Read  at  the  meeting  of  the  Pennsylvania  Pharmaceutical  Association, 
June,  1913. 
