HINTS  TO  DISPENSERS. 
351 
the  last,  and  immediately  shaken  gently.  Hydrocyanic  acid 
should  be  added  last  of  all.  Nitrate  of  silver,  diacetate  of  lead, 
and  other  salts  decomposed  by  ordinary  water,  should  be  dis- 
solved in  distilled  water. 
The  following  queries  may  here  be  put : — What  does  a  medi- 
cal man  intend  when  he  expresses  the  quantity  of  any  powerful 
medicine  in  a  mixture  by  the  term  guttas  f  Does  he  really 
mean  drops,  or  is  he  under  the  impression  that  the  difference 
between  drops  and  minims  is  so  trivial  as  not  to  necessitate  his 
particularizing?  When  the  term  "  ad  Octarius  "  occurs,  which 
is  intended,  a  sixteen  or  twenty  ounce  mixture  ?  Is  it  generally 
understood  that  unless  the  prescriber  specifies  P.B.  "he  means 
P.  L  ? 
The  next  class  to  be  noticed,  are  pills  and  powders.  With 
respect  to  the  latter,  the  best  mode  of  obtaining  a  uniform  admix- 
ture, perhaps,  is,  by  weighing  and  rubbing  well  together  the 
smaller  quantities  first,  and  then  adding  the  larger  ones  gradu- 
ally ;  and  in  cases  where  large  quantities  of  bulky  powders  are 
ordered,  by  sifting.  As  to  their  division  into  separate  doses, 
probably  a  practised  eye  may  be  more  safely  trusted  than  many 
a  pair  of  dispenser's  scales. 
Pills  should  be  kept  as  small  in  size  as  practicable.  In  order 
to  this,  some  of  the  soft  extracts  in  general  use  might  be  kept 
dried  down  ready  for  making  up,  or  in  the  case  of  those  seldom 
required,  by  evaporating  them  on  a  small  pill  tile  in  front  of  an 
ordinary  fire.  Rhubarb  should  be  made  up  with  some  thin 
liquid,  and  as  much  added  at  once  as  will 'be  sufficient  to  make 
up  the  mass.  Quinine  pills  may  be  kept  down  in  size  by 
reducing  the  quinine  to  a  fine  powder  before  attempting  to 
make  up. 
Some  substances  are  very  difficult  to  incorporate.  The  sul- 
phates of  zinc  and  iron  should  first  be  reduced  to  fine  powder, 
and  confection  of  hips  (that  sheet-anchor  of  the  pill-maker)  be 
used  to  bind  them  into  a  mass.  Creasote  and  essential  oils  are 
rather  troublesome  things  to  get  into  pill-masses  when  ordered 
in  large  quantities ;  some  recommend  their  being  absorbed  by 
any  powder  ordered  along  with  them,  or  added  expressly  for  the 
purpose  ;  others,  that  they  should  be  added  last ;  and  others, 
