'^'"jJne'^issr'"' }   -^^^<^^*'^^  Strength  of  Certain  Preparations.  31 1 
Granting  the  accuracy  of  the  graduates  in  use,  the  correctness  in 
reading  off,  and  the  temperature  as  influencing  expansion,  are  to  be 
taken  into  consideration,  and  it  was  from  these  views  that  the  writer 
proposed  some  months  ago  at  a  Pharmaceutical  Meeting  of  the 
Philadelphia  College  of  Pharmacy,  that  the  weight  of  a  fluid  ounce 
of  the  more  important  tinctures  of  the  old  and  the  new  pharmacopoeia 
be  ascertained. 
At  the  last  Pharmaceutical  Meeting,  lists  giving  the  results  of  such 
weighings  by  Dr.  Wolff,  Messrs.  Wiegand,  Robbins  and  Lowe,  were 
presented  and  referred  to  the  writer  for  proper  arrangement.  All 
these  weighings  were  made  within  the  past  two  months,  when  the 
temperature  varied  but  little  from  60°  F.  In  one  series  a  narrow 
tube  was  used,  properly  gauged  to  one  fluid  ounce ;  in  another  series  a 
specific  gravity  (1000  grain)  bottle  was  used  and  the  weight  of  a  fluid 
ounce  ascertained  by  calculation ;  in  two  series  graduates,  the  correct- 
ness of  which  had  been  proven,  were  employed.  The  results  are  in 
nearly  all  cases  practically  alike,  the  variation  of  the  weights  being 
mostly  insignificant,  and  of  no  influence  on  the  average  dose ;  they  are 
such  merely  as  may  always  be  expected  when  measures  of  capacity  of 
the  form  generally  in  use,  are  employed ;  in  a  few  cases  the  weights 
scarcely  exceed  that  of  a  fluid  ounce  of  officinal  alcohol  at  60°  F. 
(373-6  grains.) 
In  the  following  table  the  lowest  (X)  and  highest  (i?)  weights  are 
given,  together  with  the  mean  (m)  of  all  results ;  when  only  one  deter- 
mination was  made,  or  when  the  results  were  identical,  the  weight  has 
been  placed  in  the  column  of  average  weights.  The  column  giving 
the  weight  of  active  drug  necessarily  gives  the  theoretical  weight 
U.  S.  P.,  1870,  without  taking  into  consideration  the  actual  variations 
in  measure. 
When  calculated  from  the  proportions  stated  in  the  table  of  the 
Pharmacopoeia,  the  following  figures  are  obtained  as  representing  the 
assumed  weight  of  the  active  drug  contained  in  one  fluidounce :  tinct. 
aeon.  rad.  151 '26,  tinct.  calumbse  40,  tinct.  capsici  21 '43,  tinct.  lobe- 
lise  80,  tinct.  myrrhse  75,  tinct.  opii  and  tinct.  opii  deod.  41*7,  tinct. 
Valerianae  80,  spiritus  camphorse  40  grains.  It  will  be  observed  that 
five  of  these  tinctures,  as  they  would  be  dispensed,  show  less  variation 
from  those  of  the  old  Pharmacopoeia  than  is  shown  by  calculation, 
while  the  remaining  three  are  somewhat  stronger,  and  spirit  of  cam- 
phor is  slightly  weaker. 
