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ON  THE  PRESERVATION  OF  FLUID  EXTRACTS. 
is  not  that  by  it  two  or  three  ways  of  decay  are  excluded  ;  an 
equally  important  advantage  is  that  by  its  presence,  in  greater 
or  less  proportions,  valuable  medicinal  principles  are  obtained 
that  otherwise  would  not  be  extracted. 
Iodide  of  iron  possesses  no  qualities  calculated  to  produce 
changes  in  a  solution  of  sugar;  it  belongs  to  the  mineral  king- 
dom. Let  us  take  an  illustration  from  the  vegetable  kingdom. 
Saussure  found  that  during  twenty-eight  days,  oil  of  lemon  ab- 
sorbed each  day  twice  its  own  volume  of  oxygen.  To  this  ab- 
sorption is  due  its  proneness  to  change.  If  to  one  fluid  pound 
of  simple  syrup  we  add  one  ounce  of  fresh  oil  of  lemon,  and  to 
one  fluid  pound  of  alcohol  we  add  one  ounce  of  the  oil,  which 
menstruum  will  longest  preserve  the  oil  from  change  ? 
Although  the  use  of  essential  oils  to  improve  the  flavor  of 
fluid  extracts  may  be  admissible,  I  do  not  see  how  they  can  be 
called  "  antiseptics  similar  to  alcohol,"  when  they  so  easily  and 
rapidly  undergo  change  by  absorbing  oxygen,  and  do  not  act  by 
abstracting  moisture  from  membranes  and  all  similar  substan- 
ces." 
There  is  no  better  illustration  of  the  subject  of  transparency 
in  fluid  extracts,  than  the  cincho-tannates  already  alluded  to. 
In  making  fluid  extract  of  calisaya  bark,  these  principles  are 
copiously  deposited  during  evaporation,  neither  water  or  sugar 
will  dissolve  them  ;  by  the  use  of  close  flannel  we  lose  them,  but 
the  presence  alcohol  in  proper  proportion  dissolves  them.  I 
believe  this  to  be  a  speaking  example  in  favor  of  the  employ- 
ment of  alcohol. 
Recapitulating  the  points  treated  on,  the  article  gives  the 
following  as  the  sixth  reason  to  prove  "  the  superiority  of  sugar 
over  alcohol."  "By  the  addition  of  a  slight  quantity  of  alco- 
hol when  necessary,  the  tendency  to  fermentation  and  moulding 
will  be  effectually  counteracted."  Exactly. 
It  may  be  that  in  some  instances  where,  from  the  nature  of 
the  case,  a  formula  cannot  be  devised  which  will  at  all  times  and 
seasons  be  applicable,  a  departure  therefrom  may  be  justifiable, 
but  to  allow  such  departures  can  hardly  be  safe,  as  a  general 
rule.  Fortunately,  in  the  case  of  fluid  extracts,  no  such  difficulty 
exists,  as  formulae  can  be  adopted  which  will  be  universally 
applicable. 
