'^'"•yu^y'-ifso'""*}        Remarks  on  Syrupus  Guaiaci.  345 
SOME  REMARKS  ON  SYRUPUS  GUAIACI. 
By  T.  C.  Craig,  Ph.G.,  M.D. 
In  the  "American  Journal  of  Pharmacy"  for  1876,  March  No., 
page  139,  the  following  formula  appears: 
Syrupus  Guaiaci. 
B     Pulveris  guaiaci,         ....  ^^''^ii 
Liquoris  potassse,  ...  .  f^^s 
Sacchari  albi,  .  .  .  .       tbi  (avoird.) 
Aquae,  .  .  .  .  .  f^viii 
Fiat  syrupus.    Signa — Dose,  a  teaspoonful^  containing  5  grains  of  guaiacum. 
Having  had  occasion  to  make  syrup  of  guaiac  quite  a  number  of 
times,  and  using  this  formula,  I  was  surprised  at  finding  very  much  of 
a  residue  left  after  making  the  syrup.  As  each  teaspoonful  of  the 
syrup  was  to  contain  five  grains  of  guaiacum,  I  thought  it  strange  that 
so  much  of  it  should  remain  insoluble  ;  hence  I  was  led  to  investigate 
the  subject  and  discover  the  fallacy  if  any  existed. 
I  noticed  that  if  I  added  a  solution  of  caustic  potash  to  the  residue 
and  filtered  it  the  filtrate  was  dark  brown,  almost  black.  From  this  I 
concluded  that  the  amount  of  solution  of  caustic  potash  prescribed  in 
the  formula  was  insufficient  to  extract  the  active  principles  of  the  gua- 
iacum, and  that  the  reason  I  had  so  much  residue  was  that  more  caus- 
tic potash  was  needed;  but  how  much.?  This  I  determined  in  the 
following  way:  According  to  recent  authority  (National  Dispensatory) 
guaiac  resin  contains,  as  its  active  principles,  guaiaconic  acid  and  gua- 
iaretic  acid,  the  former  to  the  amount  of  seventy  per  cent. ;  the  latter, 
ten  per  cent. 
The  chemical  formula  for  guaiaconic  acid  is  CggH^oO^Q,  and  for  guai  • 
aretic  acid  is  Q^^Yi^^O^.  The  combining  weight  of  guaiaconic  acid  is 
656  and  that  of  guaiaretic  acid  is  330.  The  combining  weight  of 
caustic  potash  (KHO)  is  56. 
Now,  to  neutralize  656  atoms,  molecules  or  grains  of  guaiaconic 
acid  will  require  56  parts  of  caustic  potash  ;  again,  to  neutralize  330 
atoms,  molecules  or  grains  of  guaiaretic  acid  will  require  56  parts  of 
caustic  potash  ;  then  656,  the  guaiaconic  acid,  plus  330  of  guaiaretic 
acid  will  require  112  parts  of  caustic  potash  to  neutralize  them. 
Guaiac  resin  consists,  as  before  stated,  of  70  per  cent,  guaiaconic 
acid  and  10  per  cent,  guaiaretic  acid — 80  per  cent,  in  all,  or  80  grains 
in  every  hundred  grains  of  the  resin.  According  to  our  formula  eight- 
tenths  of  all  the  guaiac  resin  should  be  dissolved,  /v.,  eighty  grains  out 
