PHARMACEUTICAL  OBSERVATIONS  ON  BUCHU.  487 
them  until  another  pint  is  obtained,  washing  them  with  water, 
if  necessary,  to  make  up  the  measure;  mix  this  with  the  pint  last 
obtained,  and  evaporate  on  a  water  bath  to  four  fluid  ounces;  add 
this  to  the  four  ounces  left  after  the  spontaneous  evaporation. 
The  resulting  fluid  extract  should  measure  eight  fluid  ounces  ;  if 
less  than  that,  the  deficiency  can  be  made  up  by  the  addition  of 
diluted  alcohol.  Fluid  extract  of  buchu  as  thus  prepared  is  of  a 
dark  green  color,  and  has  the  odor  and  taste  of  the  leaves  in  a 
concentrated  form.  I  have  tried  several  ways  of  making  this  ex- 
tract, but  have  found  none  so  satisfactory  as  the  above.  The 
first  was  with  twelve  fluid  ounces  of  alcohol  and  four  of  ether  to 
eight  ounces  of  leaves,  mixing  the  alcohol  and  ether  with  the 
buchu  without  previous  maceration,  then  displacing  a  pint  by 
the  addition  of  diluted  alcohol.  Set  this  aside  to  evaporate  spon- 
taneously until  reduced  to  four  fluid  ounces.  Upon  the  mass  in 
the  percolator  I  poured  diluted  alcohol  until  ten  fluid  ounces  had 
passed,  and  evaporated  this  in  a  water-bath  to  four  ounces,  then 
mixed  them  ;  this  was  of  a  very  dark  color,  and  tasted  quite 
strongly  of  the  leaves ;  but  in  evaporating  spontaneously,  a  re- 
sinous matter  was  deposited  on  the  sides  of  the  evaporating  vessel 
and  would  not  mix  smoothly  with  the  extract. 
I  next  made  an  extract  according  to  the  above  formula,  to 
which  I  added  an  ounce  of  sugar  to  an  ounce  of  extract;  this  did 
not  possess  any  advantages  over  the  other.  Another  was  then 
prepared  in  the  same  proportions  as  before,  and  conducted  in 
the  same  manner  in  the  first  part  of  the  process,  but  to  the  mass 
in  the  percolator  I  added  water,  holding  carbonate  of  potassa  in 
solution ;  this  was  allowed  to  percolate  twenty-four  hours,  then 
expressed,  and  evaporated  to  the  same  quantity  as  the  first,  and 
mixed. 
The  object  of  adding  carbonate  of  potassa  is  to  dissolve  out 
two  substances  noticed  by  Brandes,  and  called  by  him  brown 
substance  extracted  by  potash,  and  nitrogenous  substance  ex- 
tracted by  potash.  Ether  and  alcohol  I  supposed  would  dissolve 
the  volatile  oil  and  resin,  and  the  presence  of  the  alkali  in  the 
watery  infusion  prevents  its  subsequent  precipitation.  Water, 
according  to  the  same  chemist,  dissolves  the  bitter  extractive,  or 
what  he  terms  diosmin,  which  he  says  is  insoluble  in  alcohol  and 
ether  but  soluble  in  water.    I  found  an  advantage  in  adding  a 
