338 
CHLOROFORM  LINIMENT  IN  TOOTHACHE. 
its  volume  per  cent,  of  water,  the  thickish  liquid  is  formed. 
The  ether — the  upper  layer — when  mixed  with  a  little  water, 
takes  up  rather  more  tannic  acid  than  the  anhydrous  ether.  I  find 
that  the  upper  layer — pure  ether  with  1  vol.  p.  c.  of  water — 
takes  up  1-2  p.  c.  tannic  acid. 
This  result  appears  to  confirm  Pelouze's  view.  It  is  not,  how- 
ever, true  that  the  syrupy  layer  is  a  concentrated  aqueous  solu- 
tion of  tannic  acid.  On  carefully  removing  a  portion  of  this 
liquid,  so  that  none  of  the  upper  stratum  may  mix  with  it,  in- 
troducing it  into  a  retort,  and  distilling  with  good  condensation, 
considerable  frothing  takes  place  at  first,  and  ether  passes  over, 
followed  by  water,  the  two  liquids  forming  layers  of  equal 
depth  in  a  cylindrical  receiver. 
If  a  little  water  be  added  to  these  two  liquids,  a  third  layer 
is  formed,  which  rests  between  the  two,  and  is  therefore  insolu- 
ble both  in  ether  and  in  water.  This  behaviour  appears  to  me 
to  render  probable  the  existence  of  a  chemical  compound  of  tan- 
nic acid,  ether,  and  water,  possibly  an  acid  ethyl-salt  constituted 
like  ethyl-sulphuric  acid,  that  is  to  say,  a  tannate  of  ether  and 
water. 
There  is  a  practical  deduction  from  these  experiments  which 
deserves  to  be  mentioned.  The  behaviour  of  pulverized  and  well 
dried  tannic  acid  to  ether,  is  so  peculiar  that  it  may  be  used  as 
a  test  of  the  presence  of  water  in  that  liquid.  In  anhydrous 
ether  the  powder  remains  quite  unaltered,  but  in  hydrated  ether 
it  cakes  together  or  deliquesces  to  a  thickish  syrup,  according 
to  the  amount  of  water  present,  and  the  quantity  of  tannic  acid 
added.  Very  small  quantities  of  tannic  acid  gave  a  distant  re- 
action London  Pharm.  Journ.  March^  1861/rom  The  Quar- 
terly Journal  of  the  Chemical  Society. 
CHLOROFORM  LINIMENT  IN  TOOTHACHE, 
Take  the  white  of  an  egg,  and  add  an  equal  bulk  of  chloroform, 
and  digest  four  hours  at  an  ordinary  temperature.  Apply  this 
to  the  gum,  immediately  above  the  aching  tooth,  by  saturating  a 
piece  of  lint,  over  which  is  to  be  placed  a  second  piece  of  dry 
lint  larger  than  the  first,  in  order  to  protect  the  lips,  which  are 
to  be  allowed  carefully  to  fall  on  the  two  in  order  to  retain  them 
