Am.  Jour.  Pharm. 
May,  1897. 
Pharmacopoeial  Preparations. 
253 
two  specimens  prepared  in  November,  1895,  with  water  from  the 
Brighton  constant  supply,  which  is  a  very  calcareous  water ;  one  is 
a  simple  solution  of  the  perchloride,  and  the  other  has  an  equal 
weight  of  pure  chloride  of  sodium  added.  The  latter  you  will 
observe  has  deposited  much  more  than  the  former,  in  which  there 
is  hardly  a  trace  of  deposit.  This  strongly  illustrates  the  undesira- 
bility  of  tampering  with  solutions  in  order  to  make  them,  as  we 
consider,  more  stable ;  in  fact,  with  few  exceptions  no  preservative 
should  be  added  to  a  pharmacopoeia  preparation  unless  the  label 
indicates  boldly  that  it  is  there.  While  on  the  subject  of  mercuric 
salts,  I  should  like  to  illustrate  the  importance  of  having  our  lime 
water  of  full  strength,  and  well  preserved. 
In  making  the  yellow  mercurial  lotion  of  the  B.P.,  which  has  18 
grains  of  sublimate  to  10  ounces  of  lime  water  ;  if  the  lime  water  be 
only  three-fourths,  or  from  keeping,  so  low  as  one-half  the  pharma- 
copoeial strength,  a  brick-red  preparation,  an  oxychloride  is  pro- 
duced, rather  than  the  yellow  mercuric  oxide. 
Acetic  Acid. — Of  other  preservatives,  which  are  also  solvents  used 
officially,  acetic  acid  of  varying  strengths  is  employed,  as  in  acetum 
cantharidis  and  acetum  scillse.  This,  as  I  notice  Prof.  Remington 
recently  points  out,1  was  much  employed  in  the  pharmacy  of  the 
ancients,  sometimes  combined  with  honey  to  form  oxymels,  of  which 
we  have  inherited  both  the  vinegar  and  the  oxymel  of  squill.  Acetic 
acid  has  the  disadvantage,  however,  unless  in  a  very  concentrated 
form,  of  growing  micro-organisms  abundantly,  and  the  fungi  and 
animalculae  developed  in  brown  vinegar  must  be  well  known  to  all 
of  you.  Acetic  acid,  therefore,  besides  being  incompatible  with 
alkalies,  is  not  a  good  preservative,  although  in  some  cases  it  may 
be  a  useful  solvent. 
Sugar. — Of  the  preservatives  used  officially  which  are  not  sol- 
vents, this  is  employed  most  extensively,  not  only  with  us,  but  in 
France  and  in  the  United  States ;  in  fact,  so  much  is  this  the  case  in 
France,  that  Mr.  Ince  once  remarked  in  this  room  that  French 
pharmacy  might  be  summed  up  in  one  word,  "  sugar."  On  account 
of  its  palatability  it  of  course  meets  with  favor,  especially  among 
children.  It  enters  into  the  composition  of  all  the  syrups  and 
lozenges,  and  most  of  the  confections  and  powders,  and  is  a  useful 
preservative  from  oxidation  of  the  ferrous  preparations,  such  as  the 
1 American  Journal  of  Pharmacy \  March,  1897,  p.  121. 
