294  An  Examination  of  Commercial  Fluid  Extracts.  {AmjJne*is^arm" 
not  stated  to  have  an  appreciable  saccharine  percentage,  or  whose 
sugar,  if  present,  is  stated  not  to  possess  the  power  of  reducing 
Fehling's  solution,  was  also  the  basis  for  these  examinations. 
Such  was,  for  instance,  found  to  be  the  case  with  several  samples 
of  F.  E.  Gentian,  which  showed  by  repeated  examination  the 
presence  of  5  per  cent,  of  a  substance  corresponding  to  glucose  in 
every  respect. 
According  to  published  authorities,  gentianose,  the  sugar  present 
in  gentian  root,  does  not  reduce  Fehling's  solution.  This  has  not 
been  the  writer's  experience,  either  in  the  commercial  fluid  extract 
or  in  a  sample  which  was  prepared  strictly  according  to  the  phar- 
macopceial  directions.  The  remarkably  high  sugar  percentage  of 
some  fluid  extracts  prepared  from  ranunculaceous  plant  drugs, 
which,  on  comparison  with  similar  official  fluid  extracts,  showed  a 
vast  difference,  was  likewise  another  reason  for  this  investigation. 
Glucose  is  a  normal  constituent  of  many  plants,  also  laevulose,  or 
fruit  sugar,  which  possesses  likewise  the  property  of  reducing 
Fehling's  solution. 
In  the  process  of  preparation  of  galenical  preparations,  it  may 
also  be  produced  by  the  decomposition  of  other  compounds,  such  as 
inulin,  triticin,  particularly  in  the  presence  of  heat.  These  may 
be  regarded  as  being  some  of  the  natural  sources  of  the  sugar 
which  is  liable  to  be  present  in  fluid  extracts.  Again,  excessive 
heat  in  their  evaporation  will  have  the  effect  of  caramelizing  some 
of  the  constituents,  which,  however,  by  careful  observation  of 
pharmacopceial  directions,  is  obviated.  Besides  this,  the  claim  is 
made,  that  caramel  is  frequently  added  by  manufacturers  of  fluid 
extracts  on  a  large  scale,  for  the  purpose  of  coloring  their  prepara- 
tions. 
The  fallacious  popular  idea  that  darkness  in  color  is  an  indication 
of  strength  and  a  criterion  of  quality  is  unfortunately  also  accepted 
by  a  number  of  pharmacists. 
Caramel  also  has  the  property  of  reducing  Fehling's  solution,  and 
forms,  in  some  fluid  extracts,  when  examined  for  glucose,  an 
important  factor. 
Glucose  cannot  be  detected  with  certainty  directly  in  fluid 
extracts,  or  liquids  containing  other  vegetable  matter.  These 
compounds,  as,  for  instance,  tannin,  have  also  the  property  of 
reducing  Fehling's  solution,  and  must,  therefore,  first  be  removed. 
