AdmS', 5o2.rm' }    Dose  Measures  and  Measured  Doses.  131 
the  variation  probably  being  the  fact  that  a  colorless  fluid  is  not  so 
readily  seen  against  a  bright  shining  spoon  as  is  one  that  has  con- 
siderable color. 
Suggestion  is  a  factor  that  plays  an  important  part  in  experiments 
of  this  kind,  and  at  times,  at  least,  is  very  difficult  to  guard  against. 
Just  one  case  to  show  how  easy  it  is  to  influence  even  most  intel- 
ligent people : 
A  particularly  careful  physician  was  asked  to  measure  out  doses 
with  the  various  measures,  and  after  obtaining  several  averages  it 
was  suggested  that  he  try  measuring  teaspoonsful  of  a  colorless 
fluid  just  to  notice  the  difference  in  the  size  of  the  doses.  His 
averages  in  this  case  were  slightly  below  his  corresponding  averages 
for  the  colored  liquid.  When  told  that  his  results  in  this  particular 
test  varied  considerably  from  those  obtained  by  others,  he  volun- 
teered to  try  again,  and  despite  the  fact  that  he  asserted  the  quanti- 
ties to  be  no  larger  than  before,  his  averages  in  this  case  were  nearly 
one-fourth  greater. 
There  is  one  other  feature  of  the  personal-equation  factor  that 
might  be  mentioned  in  this  connection;  this  is  the  variation  that 
occurs  in  measuring  doses  of  medicines  that  contain  opiates.  It  is 
not  an  uncommon  occurrence  to  have  customers  who  have  this  class 
of  prescriptions  refilled  at  gradually  shortening  intervals.  This 
would  indicate  one  of  two  things  :  either  the  patient  was  taking 
more  doses  than  the  physician  prescribed,  or  his  dose-measures 
were  gradually  becoming  larger;  at  any  rate,  it  is  one  of  the  many 
possible  abuses  that  should  be  guarded  against  by  the  pharmacist. 
Having  enumerated  a  few  of  the  possible  sources  of  error  in 
measuring  doses,  the  question  naturally  arises,  Is  there  any  possible 
remedy  to  correct  these  various  discrepancies  ? 
The  solution  of  the  problem  that  suggested  itself  to  the  writer's 
mind  is  a  rather  tall  and  narrow  measuring-glass,  on  which  the  tea- 
spoonful  quantity  is  correctly  indicated.  With  such  a  medicine 
measure  there  would  be  but  slight  chance  of  any  grave  or  glaring 
error,  either  in  its  manufacture  or  its  subsequent  use. 
The  subject  of  drops  and  droppers  was  taken  up  later,  with  a 
view  of  determining  what,  if  any,  difference  existed  between  the 
drops  from  various  shapes  and  sizes  of  so-called  medicine-droppers. 
This  simple  device  is  now  in  such  general  use  in  this  country,  and 
the  number  of  very  active  drugs  that  are  measured  out  in  drop 
