468  Revision  of  the  U.  S.  Pharmacopoeia.  {Am- ^wT™' 
needs  these  tables  as  aids  to  his  commercial  operations,  which  are  not 
conducted  in  vacuo  and  rarely  at  the  temperature  of  maximum  den- 
sity, and  it  would  have  been  more  to  the  purpose  to  have  supplied 
him  with  tables  of  equivalent  weights  and  measures  computed  for 
normal  temperature  and  pressure  instead  of  at  40  C.  and  in  vacuo. 
It  is  regretted  that  in  the  adoption  of  the  Centigrade  scale  for 
temperatures  that  the  equivalent  in  the  Fahrenheit  scale  is  added 
after  each  statement  of  temperature.  The  adoption  of  the  metrical 
system  of  weights  and  measures  is  commendable  and  in  harmony 
with  scientific  works  over  the  entire  globe.  The  system  of  parts 
by  weight  adopted  by  the  Pharmacopoeia  of  1880  was  regarded  only 
as  a  compromise,  a  step  in  the  education  of  the  pharmaceutical  and 
medical  professions  toward  the  universal  adoption  of  the  metrical 
system.  With  but  few  exceptions,  such  as  making  the  dilute  acids 
and  mucilage  of  acacia,  parts  by  weight  have  been  dropped  and  the 
"un-American"  idea  of  weighing  liquids  as  a  principle  has  been 
relegated  to  the  past.  If  the  pharmaceutical  and  medical  writers 
will  now  refrain  from  transposing  these  weights  and  measures,  they 
will  compel  the  masses  to  think  in  the  metrical  system.  This  point 
attained,  they  will  soon  learn  to  understand  and  appreciate  its  use- 
fulness. 
Prior  to,  and  at  the  time  of,  the  convention  in  May,  1890,  much 
had  been  written  and  said  regarding  standardization  of  the  prepara- 
tions of  the  organic  drugs.  After  careful  consideration,  the  com- 
mittee have  introduced  methods  of  assay  for  cinchona  and  opium 
and  for  preparations  of  opium  and  nux  vomica.  We  endorse  the 
reasons  assigned  for  such  limitation  on  page  XXX.  The  lime  method 
for  assay  of  opium,  of  the  U.  S.  P.  1880,  is  discarded  and  Squibb's 
process  is  adopted,  with  the  following  slight  modifications:  Tared 
filters  are  not  used.  The  crystals  of  morphine,  after  washing  with 
water,  are  washed  with  alcohol  saturated  with  morphine  (it  is 
apparent  that  at  this  part  of  the  process  the  evaporation  of  the 
alcohol  must  be  guarded  against  or  a  slight  error  will  be  introduced), 
subsequently  washed  with  ether  and  dried  at  6o°  C.  and  transferred 
to  a  tared  watch  crystal  and  weighed.  No  test  is  applied  for  the 
purity  of  the  resulting  morphine. 
For  the  assay  of  cinchona,  the  process  of  1880  was  also  dis- 
carded and  a  modification  of  Prollius'  method  for  total  alkaloids 
adopted.    The  product  from  the  first  extraction  by  a  mixture  of 
