210 
Notes  on  Some  Chemicals. 
Am.  Jour.  Pharm. 
May,  1908. 
BISMUTH  SUBSALICYLATE. 
The  deportment  of  our  samples  to  the  test  for  limit  of  free  sali- 
cylic acid,  paragraph  6,  page  77,  U.S.P.,  was  not  anticipated,  in 
view  of  the  results  obtained  a  few  years  ago.  The  free  acid  was 
estimated  in  5  grammes  of  the  sample,  as  described  under  subgal- 
late,  with  results  varying  from  0-36  to  0  48  per  cent.  Owing  to  the 
feeble  basic  properties  of  bismuth  salicylate  and  the  readiness  with 
which  salicylic  acid  is  liberated  during  the  drying,  a  more  liberal 
allowance  must  be  made  in  the  future  for  free  (uncombined)  acid. 
Basing  such  a  test  upon  our  present  market  supply,  we  would  sug- 
gest the  following : 
"  If  1  gramme  of  the  salt  be  agitated  with  10  c.c.  of  ether,  and  the 
liquid  filtered  through  a  double  filter  of  fine  texture,  wetted  with 
ether,  the  filtrate,  when  evaporated  to  dryness,  should  not  leave  more 
than  0  004  gramme  of  residue  consisting  of  salicylic  acid." 
Among  the  other  tests  there  is  considerable  more  variation  than 
in  the  previously  mentioned  samples. 
Bi203 
HoO 
U.  S.  P. 
Per 
Per 
Free  S.  A. 
Free  S.  A. 
Sample 
Cent. 
Cent. 
Test. 
Per  Cent. 
Color.  Nitrates. 
Wt.  V< 
66-6 
0*2 
Positive. 
0-36 
Gray  white. 
0 
3-6 
2. 
62-5 
0*2 
0*40 
Yellowish  white. 
0 
1*0 
3- 
65-0 
o-3 
0-48 
White. 
0 
3*8 
4- 
66-5 
0'2 
0-36 
0 
4-2 
5- 
64'3 
0-25 
o'34 
Bright  white. 
0 
4-8 
6. 
6470 
0-3 
0-30 
White. 
0 
6-o 
March  16,  1908. 
NOTES  ON  SOME  CHEMICALS. 
By  Otto  B.  May,  Ph.D. 
STARCH  TEST    SOLUTION,  U.S.P. 
It  is  recommended  that  the  third  line  following  200  c.c,  replace 
present  text  (p.  538,  U.S.P.)  by  following :  "  Then  boil  a  few  minutes 
until  a  thin  transparent  fluid  is  obtained." 
HYDRARGYRUM  CUM  CRETA,  U.S.P. 
In  response  to  the  complaint  that  the  tests  for  mercurous  and 
mercuric  oxides  (p.  242,  U.S.P.)  are  too  exacting,  I  examined  ori- 
ginal samples  of  our  various  manufacturers.    Of  the  six  samples  ex- 
