^oVemberS-}     Review  of  Chemistry  of  the  U.S.P.  507 
cases  far  from  CP.,  to  give  their  composition  by  molecular  formulae 
is  sufficient,  to  attempt  their  structuralization  is  going  a  step  beyond 
safe  and  sound  reason.  These  formulae  are  of  interest  to  theoretical 
and  working  chemists ;  the  molecular  formula  tells  all  that  is  re- 
quired by  the  analytical  chemist.  The  druggist  of  to-day  is  not 
even  the  latter,  much  less  a  theoretical  chemist ;  hence  this  innova- 
tion is  hardly  called  for. 
Such  formulae  may  have  their  proper  place  in  the  great  reference 
work  of  the  druggist,  the  U.  S.  Dispensatory ;  they  are  matters  for 
a  reference  work,  and  not  the  working  guide.  The  German 
Arzneibuch  has  not  a  single  chemical  formula  from  the  front 
cover  to  the  back.  The  B.P.  has  one  or  two,  but  these  are  of  the 
complex  aromatics  used  as  reagents.  The  Codex  contains  both  the 
molecular  and  equivalent  formulae.  As  all  volumetric  assays  are 
really  based  on  the  latter,  their  admission  is  correct. 
The  many  complex  bodies,  the  alkaloids,  etc.,  have  not  been  in 
all  cases  sufficiently  studied  to  enable  chemists  to  give  their  struc- 
ture. This  has  led  the  commission  to  make  the  queer  break  of 
formulating  alkaloidal  salts,  the  acid  structural,  the  alkaloid  molecu- 
lar. This  is  not  in  accordance  with  good  chemical  usage.  Again, 
setting  out  the  methyl  group  in  codeine  can  but  bewilder.  Prob- 
ably it  feels  its  queer  position ! 
GASOMETRIC  ANALYSIS. 
The  commission  has  made  the  same  blunders  as  its  predecessor 
on  this  most  elegant,  rapid  and  exact  method  of  analysis.  The  gas 
burette,  nitrometer,  used,  is  not  the  best,  cheapest  or  most  practical 
style  for  the  druggist  or  chemist. 
One  table  of  corrections  has  been  added.  It  is  pleasing  to  see 
some  advance  made  over  the  1890, which  implied  barometric  pressure 
has  no  noticeable  effect  on  the  gas  volume.  The  U.S.P.,VIII,  says  that 
pressure  has  some  effect,  but  only  when  "  the  locality  is  more  than 
250  metres  above  sea  level."  The  revisers  have  forgotten  that  all 
the  estimations  take  place  in  the  presence  of  water,  and  that  the 
gas,  as  a  result,  is  saturated  therewith.  At  150  the  vapor  tension 
of  this  watery  vapor  amounts  to  only  12-7  mm.;  at  25 0  to  23  6  mm., 
and  at  300  to  only  31-6  mm.,  which  amounts  must  be  subtracted  from 
the  observed  barometric  pressure  to  give  the  true  gas  pressure. 
When  we  have  this  correct  pressure  we  may  proceed  to  apply  the 
