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Syrup  of  Tola. 
Am.  Jour.  Pharm. 
July,  1884. 
OX  SYRUP  OF  TOLU. 
By  E.  Claassex. 
The  beautiful  yellow  color  aud  the  fine  appearance  of  the  Syrup  of 
Tolu  prepared  according  to  the  formula  of  the  old  Pharmacopoeia  are, 
without  doubt,  the  reason  that  many  apothecaries  continue,  without 
making  any  tests,  to  prefer  this  syrup  to  that  made  as  the  new  Phar- 
macopoeia directs.  An  exact  answer  to  the  question,  "  Which  of  these 
two  syrups  lias  more  strength,  and  is  the  best  one  ?"  seemed  to  be, 
therefore,  both  interesting  and  useful.  For  this  purpose  I  took  equal 
quantities  of  the  syrup  prepared  from  the  Tincture  of  Tolu  by  means 
of  magnesium  carbonate  and  of  the  syrup  made  directly  from  the 
balsam.  It  is  well  known,  as  I  may  state  here,  that  all  the  effect  and 
power  of  the  Syrup  of  Tolu  is  lying  in  the  presence  in  it  of  the  benzoic 
and  cinnamic  acids.  These  two  acids  are  easily  soluble  in  ether ;  ether 
will  extract  them  readily  from  the  syrup,  leaving  of  them  behind  but  a 
small  balance.  Each  one  of  these  two  samples  of  syrup  was  therefore 
shaken  with  an  equal  volume  of  ether,  and  the  ether,  after  separation 
from  the  syrup,  evaporated  in  a  glass  dish  in  the  open  air.  The  ether 
taken  from  the  syrup  made  directly  from  the  balsam  left  a  considerable 
quantity  of  a  yellowish  white  residue  having  the  characteristic  smell 
and  properties  of  the  two  acids,  while  the  ether  shaken  with  the  syrup 
made  from  the  tincture  of  Tolu  left  behind  a  small  amount  of  resinous 
matter  only.  After  addition,  however,  of  some  hydrochloric  acid, 
enough  to  acidulate  the  syrup,  and  after  shaking  wTith  ether,  the  last 
one  left,  when  evaporated,  a  good  deal  of  the  acids.  By  this  experiment 
it  was  evidently  demonstrated,  that  in  this  syrup  the  acids  in  question 
were  not  present  in  a  free  state,  but  were  liberated  by  the  hydrochloric 
acid  added.  If  any  doubt  could  be  sustained  that  they  were  combined 
with  magnesium  in  the  syrup,  this  doubt  was  at  once  destroyed  by  the 
chemical  test  made,  viz.,  by  the  white  crystalline  precipitate  resulting 
after  the  addition  of  sodium-ammonium  phosphate.  The  magnesium 
carbonate  used  for  preparing  the  syrup  may  be  regarded  as  insoluble 
in  water ;  its  presence  in  the  syrup  is  therefore  due  to  the  acids,  which 
dissolve  a  corresponding  part  of  it  forming  magnesium  salts.  The 
determination  of  the  quantity  of  magnesium  found  present  in  any 
sample  of  syrup  of  Tolu,  that  was  shaken  after  addition  of  water  with 
magnesium  carbonate,  and  afterwards  filtered,  will  certainly  furnish  a 
