Am.  Jour.  Pharm.  \ 
August,  1902.  J 
Drops  as  Dose  Measures. 
375 
DROPS  AS  DOSE  MEASURES. 
By  M.  I.  Wii^bert, 
Apothecary  at  the  German  Hospital,  Philadelphia. 
Drops  have  been  the  subject  of  such  a  number  of  contributions 
to  medical,  as  well  as  pharmaceutical  literature,  that  any  further 
addition  would  appear  to  require  some  valid  excuse  for  being  pre- 
sented. 
Such  an  excuse  is  found  in  the  fact  that  despite  the  vast  amount 
of  work  that  has  been  done  in  this  direction,  practically  the  only 
point  that  all  investigators  agree  on  is  that  drops  differ  materially 
in  size  and  weight.  To  get  some  idea  as  to  the  present  status  of 
the  question,  the  writer  has  attempted  to  make  a  comparative  study 
of  the  views  held  by  different  investigators,  and  will  endeavor  to 
present  the  essential  features  of  these  different  views  in  as  compact 
and  condensed  a  form  as  possible. 
The  question  that  suggests  itselt  at  the  outset  is,  "  What  is  a 
drop  ?  " 
As  answer  we  might  give  a  definition,  somewhat  in  the  manner 
of  the  dictionary,  as  follows :  "A  drop  is  a  self-constituted  mass  of 
liquid  matter  held  together  by  the  attractions  of  its  molecules  and 
having  a  marked  tendency  of  assuming  a  spherical  form."  While  a 
definition  of  this  kind  describes  the  physical  properties,  shape  and 
composition  of  a  drop,  it  gives  us  little  or  no  indication  of  what  is 
meant  when  a  doctor  directs  a  medicine  to  be  taken  in  drop  doses. 
Drops  have  been  in  use  by  medical  practitioners  for  a  great  num- 
ber of  years,  but  have  always  been  considered  a  more  or  less  unsat- 
isfactory quantity,  on  account  of  the  almost  insurmountable  diffi- 
culties that  are  encountered  in  attempting  to  bring  them  within  the 
bounds  of  any  rule  or  law  by  means  of  which  their  size  or  weight 
might  be  regulated  or  determined. 
In  Volume  I  of  The  American  Journal  of  Pharmacy  we  find  an 
exhaustive  paper  by  Elias  Durand,  in  which  the  writer  calls  atten- 
tion to  the  variation  in  the  size  of  drops  and  their  unreliability  as 
measures  of  capacity.  Besides  giving  a  list  of  the  number  of  drops 
necessary  to  equal  20  minims,  or  to  weigh  20  grains,  the  writer  also 
makes  some  interesting  observations,  a  few  of  which  we  will  have 
occasion  to  refer  to  later.  He  also  makes  an  interesting  historical 
statement,  but  unfortunately  does  not  give  any  dates.  According 
