520  Revision  of  the  U.  S.  Pharmacopoeia.   { Am^.r;iSfrm" 
told,  indicates  by  the  absence  of  color  produced  "  absence  of  alde- 
hyde, etc."  What  is  meant  by  "  etc.;"  we  presume  ozone  and  hydro- 
gen peroxide  ? 
We  now  have  Alcohol,  Absolute  Alcohol,  Deodorized  Alcohol  and 
Diluted  Alcohol,  all  official.  Absolute  alcohol  should  be  placed  with 
the  reagents  and  test  solutions.  The  official  alcohol  should,  likewise, 
be  required  to  conform  to  the  percentage  and  tests  for  deodorized 
alcohol  and  the  latter  title  dropped.  The  difference  in  commercial 
value  between  the  two  grades  during  the  past  year  has  only  been 
from  5  to  10  cents  per  gallon.  The  U.  S.  P.,  1880,  required  alcohol 
to  stand  the  sulphuric  acid  test  which  is  now  given  as  the  distin- 
guishing test  between  these  grades. 
Diluted  alcohol  is  again  made  from  equal  volumes  of  alcohol  and 
water,  and  is  41  per  cent,  by  weight  or  48-6  per  cent,  by  volume, 
instead  of  being  53  per  cent,  by  volume,  as  in  1 880. 
The  rules  for  making  a  lower  percentage  of  alcohol  from  a  higher 
percentage  should  be  attached  to  the  alcohol  table  in  the  appendix 
and  not  incorporated  in  the  body  of  the  book. 
Purified  Aloes  remains.  There  may  be  some  reason  for  directing 
its  use  in  the  pills  containing  that  article  and  in  compound  extract 
of  colocynth,  but  in  the  various  tinctures  which  are  necessarily 
filtered,  the  Socotrine  aloes  might  have  been  directed.  The  use  of 
aloes  and  not  purified  aloes  in  these  tinctures  appears  to  be  universal. 
Aloin  is  a  newly  admitted  remedy.  It  is  to  be  remarked  that  as 
one  of  the  principal  uses  of  a  Pharmacopoeia  is  to  prevent  uncer- 
tainty, to  fix  definite  standards,  it  would  have  been  well  to  have 
recognized  only  barbaloin  under  that  title,  especially  as  it  consti- 
tutes almost  entirely  the  aloin  of  commerce. 
Dried  Alum  is  now  manufactured  in  such  quantities  and  at  such 
reasonable  price  that  its  preparation  is  seldom,  if  ever,  attempted 
by  the  pharmacist  and  so  the  process  of  manufacture  might  have 
been  omitted.  Aluminum  Hydrate  should  have  been  omitted  ;  use 
would  not  necessitate  its  retention. 
Ammonium  Carbonate  is  tested  for  empyreumatic  substances  by 
supersaturating  with  nitric  acid  and  evaporating  to  dryness  when  a 
colorless  and  odorless  residue  should  be  obtained  ;  the  permanganate 
test  of  the  Pharmacopoeia,  1880,  being  discarded.  It  is  titrated 
with  normal  sulphuric  acid  solution,  using  rosolic  acid  as  an  indi- 
cator.   But  why  not  direct  that  2-613  grm.  of  the  salt  be  dissolved 
