224  MorpJiiometric  Assay  of  Opium,      { '^Va"^', 
Pharm. 
1871. 
peppermint,  which  they  lightly  apply  to  the  seat  of  pain  with  a  camel- 
hair  pencil.  Since  then,  in  my  own  practice,  I,  in  the  same  way,  fre- 
quently employ  oil  of  peppermint  as  a  local  anaesthetic,  not  only  in 
neuralgia,  but  also  in  gout,  with  remarkably  good  results  ;  indeed,, 
the  relief  from  pain  I  have  found  to  be  almost  instantaneous." 
It  is  worthy  of  note  that  som.e  Chinese  pharmaceutists  in  San 
Francisco  and  New  York  have  been  selling  a  remedy  for  neuralgia 
which  has  gained  some  repute.  It  is  a  liquid,  put  up  in  very  small 
vials,  holding  about  half  a  drachm  each,  which  are  sold  at  an  exorbitant 
price.  The  liquid  has  a  strong  smell  of  peppermint,  and  is,  in  all 
probability,  the  oil  of  that  plant. — Tlie  Medical  News  and  Library y 
Jan.,  1871. 
MORPHTOMETRIC  ASSAY  OF  OPIUM. 
By  Dr.  Theodore  Schlosser. 
The  author  regards  Mohr's  process,  with  the  ingiprovements  sug- 
gested by  Jakobson  and  Hager,  as  the  most  advantageous.  He  ope- 
rates as  follows :  200  grains  of  opium  are  digested  over  night  in  a 
tared  8  oz.  flask  with  2  oz.  distilled  water,  until  a  uniform  mixture, 
free  from  lumps,  is  obtained.  50  grs.  recently  prepared  burned  lime 
are  slaked  with  about  20  drops  of  distilled  water,  then  mixed  with 
1  oz.  of  water  and  added  to  the  opium  infusion.  Water  is  now  added 
until  the  mixture  weighs  1850  grains  (1600  water,  200  opium,  50 
lime).  The  flask  is  then  kept  in  boiling  water  for  one  hour,  and  its 
hot  contents  poured  on  a  small  filter,  which  has  7iot  been  previously 
moistened,  but  is  kept  covered  with  a  glass  plate.  Neither  flask  nor 
filter  are  rinsed  with  water.  The  filtrate  is  then  weighed  and  3  per 
cent,  deducted  therefrom  ;  the  remaining  figure  represents,  according 
to  the  author's  investigations,  the  weight  of  pure  water  contained  in 
the  filtrate.  If  the  filtrate  weighs  1100  grains,  it  contains  1067 
(1100—33)  grs.  water,  and  represents  1600:1067::200:133  grs.  opium. 
The  filtrate  is  heated  in  a  water-bath,  70  grs.  granulated  chloride  of 
ammonium  are  dissolved  in  it  by  careful  agitation,  the  whole  again 
heated  in  a  water-bath,  and,  after  cooling,  40  grs.  ether  are  mixed  in 
by  agitation,  and  the  whole  set  aside  for  an  hour.  Should  the  ether 
not  have  completely  prevented  the  adhesion  of  the  morphia  to  the 
glass,  warm  water  is  poured  upon  the  outside  of  the  flask,  when  the 
alkaloid  can  be  readily  detached,  and  is  collected  upon  a  small  filter, 
washed  with  an  ounce  of  water  and  dried.    Narcotina  is  removed  by 
