ON  THE  DROP  AND  MINIM  MEASURE. 
429 
which  it  falls — also  that  it  varies  according  to  the  density  and 
viscosity  of  the  fluid,  and  according  to  some  other  of  its  quali- 
ties not  yet  well  understood. 
There  can  be  no  doubt  that  it  would  be  much  better  on  the  part 
of  the  prescriber  to  do  away  with  the  term  "  gtt."  altogether  ; 
but  while  it  is  used,  sometimes  to  express  a  minim,  and  some- 
times two-thirds  of  a  minim,  and  sometimes  a  drop,  with- 
out any  definite  idea  of  its  value,  it  remains  with  us  to 
decide,  as  best  we  can,  how  much  tincture  of  digitalis  or 
hydrocyanic  acid  is  to  be  used  in  obedience  to  the  physician's 
order  of  "gtt.  xij."  If  all  were  agreed,  it  would  probably  be 
best  to  understand  minims  when  guttse  are  prescribed,  which 
uniformity  of  practice  might  probably  be  obtained  by  adding  a 
note  to  the  table  of  measures  in  the  Pharmacopoeia,  to  the  effect 
that  minims  shall,  for  the  future,  take  the  place  of  drops  ;  and 
this  would  probably  also  expedite  the  disuse  of  the  ambiguous 
term  by  the  profession. 
There  are,  however,  certain  circumstances  under  which  quan- 
tity may  be  advantageously  estimated  by  drops.  If  a  few 
minims  of  a  powerful  tincture  are  ordered  in  a  draught,  the 
minim  meter  is  at  once  convenient  and  accurate ;  but  if  a  few 
minims  of  oil  are  to  be  added  to  a  pill  mass,  the  case  is  other- 
wise— the  proportion  adhering  to  the  measure  being  large  and 
difficult  of  removal. 
With  the  view  of  facilitating  accuracy  in  such-like  cases,  I  have 
ascertained  the  number  of  drops  equal  to  fjjj.  of  various  essential 
oils,  &c,  when  dropped  from  the  bottles  in  which  they  are  re- 
spectively kept,  and  have  marked  these  numbers  permanently 
upon  the  bottles,  thus — 01.  Menth.  P.,  110 ;  01.  Caryophyl, 
90  ;  so  that  if  n\,xij.  of  either  of  these  are  prescribed,  twenty- 
two  drops  of  the  former  or  eighteen  of  the  latter  may  be  used. 
It  is  not  necessary  to  trouble  about  the  comparative  fluidity  of 
the  various  liquids,  or  the  thickness  of  the  bottle  lip  ;  but  it  is 
necessary  to  see  that  the  dropping  is  always  performed  in  the 
same  manner  :  fifty-four  drops  of  hydrocyanic  acid  equalled 
when  each  drop  fell  clearly  from  the  lip  of  the  phial ;  but  if  the 
stopper  were  not  entirely  removed,  and  the  drop  fell  conjointly 
from  the  stopper  and  lip  of  the  phial,  thirty-two  drops  filled  the 
same  measure. 
