128  Dose  Measures  and  Measured  Doses.  {AmMi?ch,f902.rm* 
This  actual  variation  in  shape,  size  and  capacity  of  medicine, 
glasses  is  but  one  side  of  the  problem  ;  another,  and  probably  a  much 
more  important  part,  is  played  by  the  personal  equation,  or  ability, 
of  the  person  that  is  actually  doing  the  measuring.  This  factor  is 
usually  lost  sight  of  in  discussions  of  this  kind,  but  is  really  of  con- 
siderable moment,  especially  when  we  consider  that  doses  are 
necessarily  measured  by  all  classes  and  kinds  of  people  that  may,  or 
may  not,  have  had  training  in  this  particular  direction. 
To  get  some  approximate  ideas  as  to  the  real  importance  of  this 
personal  equation  factor,  we  have  made  several  hundred  investiga- 
tions or  trials  on,  or  with,  upwards  of  a  hundred  people.  Repre- 
sentative medicine  measures  were  taken,  and  the  various  persons  were 
requested  to  measure  out  ten  doses,  just  as  though  they  were  to  be 
given  to  a  patient.  For  the  liquid,  a  diluted  alcohol,  slightly  colored 
with  caramel,  was  used.  An  alcoholic  mixture  was  chosen  so  as  to 
reduce  as  much  as  possible  the  error  resulting  from  portions  of  the 
liquid  remaining  adherent  to  the  sides  of  the  glass.  The  doses 
were  measured  into  a  beaker  or  glass  tumbler  so  as  to  avoid  any 
suggestion  that  might  be  offered  by  the  lines  and  figures  on  ihe 
sides  of  a  graduate.  The  total  quantity  was  later  measured,  and 
this  total,  divided  by  ten,  gave  us  the  average  for  the  individual  doses. 
By  measuring  twenty  doses  alternately,  in  two  separate  tumblers,  it 
was  found  that  the  averages  were  remarkably  even,  so  that  for  all 
Table  No.  5— SHOWING  HIGHEST,  LOWEST  AND  AVERAGE  QUANTITIES 
MEASURED  FROM  THE  SAME  MEASURE  BY  VARIOUS  PERSONS. 
TEASPOONS. 
Glass  No. 
TABLESPOONS. 
High. 
Low. 
Average. 
High. 
Low. 
Average. 
36 
1*5 
2'5 
4 
15-2 
11  6 
144 
3-4 
2"I 
3"o 
5 
I4'5 
io-8 
12-8 
3*5 
i-8 
26 
6 
13-8 
■  n'5 
12-6 
4'9 
3'o 
3'9 
13 
i'6'6 
I2'0 
14-2 
5'2 
3'i 
3-8 
14 
16-6 
I2'0 
15-0 
4*4 
3*5 
4'i 
15 
162 
i4'o 
14  8 
6-o 
3-2 
4"4 
17 
l6"2 
12-3 
14-9 
7'o 
3-o 
5*o 
Spoon. 
18-0 
8-9 
14  0 
4*2 
2'0 
3'2 
Med.  spoon. 
16-4 
122 
14-2 
5'i 
4'5 
4-8 
Special. 
I5'2 
14*6 
14-9 
