Amfi°bU,r'i8P79arm'}    Linimentum  Terebinthina  Aceticum.  97 
same  proportion  of  acetic  acid  as  in  the  Pharmacopoeia,  i.  *.,in  relation 
to  the  whole  quantity  of  liniment,  the  formula  would  be — 
No.  4. 
Turpentine,  .  .  .  .  .4  parts. 
Liniment  of  Camphor,  .  .  4  " 
Glacial  Acetic  Acid,  .  .  .  .1  part. 
Should  spirit  be  considered  a  desirable  ingredient  of  the  liniment,  of 
course  No.  1  may  be  adopted,  but  it  will  be  perceived  that  the  propor- 
tion of  glacial  acid  in  this  formula  is  1  in  6.  If  this  be  thought  too 
much,  the  following  may  be  a  satisfactory  formula  : 
No.  5. 
Glacial  Acetic  Acid,  .  .  .  .1  gart. 
Spirit  of  Camphor,        ....  3  parts. 
Castor  Oil,  .  .  .  .  .    2  " 
Turpentine,    .  .  .  .  2  " 
Mixed  in  the  above  order. 
Of  course  it  is  a  medical  rather  than  a  pharmaceutical  question  as  to 
which  of  the  above  formulae  may  be  the  best,  but  as  it  has  been  stated 
to  me  that  it  is  not  desirable  to  increase  the  proportion  of  acetic  acid, 
I  should  say  that  No.  4  is  the  preferable  one. 
It  may  be  well  to  say  that  the  above  liniments  were  made  with  glacial 
acetic  acid  from  a  respectable  London  house,  labelled  "  solid  at  500," 
but  which  has  actually  crystallized  at  5 2°,  and  the  crystals  have  not 
completely  dissolved  in  a  day  in  a  temperature  of  580  to  620,  so  that 
it  is  stronger  than  the  Pharmacopoeia  acid,  which  "  crystallizes  when 
cooled  to  340,  and  remains  crystalline  until  the  temperature  rises  to 
above  480."  On  mixing  only  5  per  cent,  of  acetic  acid,  B.  P.,  with 
the  above  acid,  none  of  the  above  formulae  gave  satisfactory  results. 
Probably  it  may  be  said  that  no  simpler  or  more  quickly  applied  test 
of  the  strength  of  glacial  acetic  acid  has  hitherto  been  suggested  than 
the  making  of  this  liniment.  With  regard  to  the  point  of  crystalliza- 
tion, and  as  an  illustration  of  the  apparent  anomalies  so  fully  discussed 
by  Mr.  Tomlinson  in  his  paper  on  "  Supersaturation,"  I  have  had  the 
same  glacial  acetic  acid  in  a  similar  bottle,  exposed  during  a  night  to  a 
temperature  of  49 0  without  crystallizing  :  but  on  dropping  in  a  crystal 
it  was  at  once  converted  into  a  solid  mass. 
Has  not  this  subject  also  some  bearing  on  the  discussion  as  to  the 
solubility  of  Magnesium  sulphate  as  contrary  to  Mr.  Brown's  experi- 
ence ?  I  do  not  find  Howard's  magnesium  sulphate  even  remain  in 
solution  in  its  own  weight  of  distilled  water  at  6o°. — Pharm.  your,  and 
Trans.,  Dec.  21,  1878. 
7 
