A  janua&,Pi906.nj'}      Inorganic  Chemistry  of  the  U.S. P.  21 
There  are  a  few  minor  changes  in  the  tests.  The  tannic  acid  test  is 
given,  the  introduction  of  which  is  a  good  one,  in  that  it  reminds 
one  of  the  fact  that  tannic  acid  is  an  antidote  to  antimony.  The 
volumetric  assay  is  slightly  though  advantageously  modified.  The 
salt  should  contain  not  less  than  99/5  per  cent,  of  pure  salt,  against 
IOO  per  cent,  in  the  old  U.S. P. 
Aqua  Ammonia. — The  volumetric  assay  directs  3  c.c.  of  ammonia 
water  be  accurately  weighed  in  a  weighing  bottle,  50  c.c.  of  distilled 
water  added  and  then  titrated  with  normal  sulphuric  acid  V.  S., 
using  litmus  or  methyl  orange  as  indicator.  In  the  old  process 
rosolic  acid  was  used. 
Aqua  Hydrogenii  Dioxidi. — As  previously  stated,  no  official  pro- 
cess for  the  preparation  of  this  compound  is  given.  There  is  no 
important  change  either  in  the  tests  for  identity  or  impurities  or  in 
the  assay  process.  The  explicit  directions  given  in  the  old  Phar- 
macopoeia as  regards  the  expressing  of  the  results  of  the  analysis  in 
grammes  of  absolute  hydrogen  dioxide  and  grammes  and  volume  of 
available  oxygen  are  omitted. 
Silver  Salts. — Outside  of  those  previously  noted  there  are  no  im- 
portant changes  in  the  silver  salts.  An  improvement  in  the  method 
of  assaying  is,  however,  worth  noting.  In  this  the  silver  salt,  dis- 
solved in  a  prescribed  quantity  of  distilled  water  (not  "  water  "  as 
before),  is  treated  with  a  measured  excess  of  tenth-normal  sodium 
chloride  V.  S.,  and,  after  the  addition  of  3  drops  of  potassium 
chromate,  titrated  with  tenth-normal  silver  nitrate  V.  S.,  to  a  perma- 
nent red  color.  In  the  old  Pharmacopoeia  the  silver  salt  was  titrated 
with  the  sodium  chloride  V.  S.,  until  complete  precipitation  resulted. 
The  proper  performance  or  this  required  that  the  precipitate  be 
allowed  to  settle  after  each  addition  of  the  sodium  chloride  solution 
in  order  that  one  could  see  if  its  further  addition  produced  any  more 
precipitate  ;  thus  much  time  was  consumed  in  waiting. 
Aurii  et  Sodii  Chloridum. — The  gravimetric  assay  process  of  the 
old  Pharmacopoeia  is  replaced  by  a  new  process,  which  latter  depends 
upon  reducing  the  gold  to  the  metallic  state  by  boiling  its  alkaline 
solution  with  hydrogen  dioxide,  and  weighing  the  resulting  precipi- 
tate after  washing  and  ignition. 
Bismuth  Salts. — There  are  two  new  bismuth  salts — the  subgallate 
and  the  subsalicylate.  The  bismuth  salts  are  assayed  gravimetrically 
by  reduction  to  bismuth  oxide.  The  presence  of  arsenic  as  an  im- 
purity is  detected  by  Bettendorfs  test. 
