94 
Benzoic  Acid  from  Urine. 
Am  Jour.  Pharm 
Feb.,  1884. 
in  the  table  of  .solubilities  of  the  Pharmacopoeia  (page  426)  under  the 
head  of  ammonium  chloride;  at  present  it  reads:  1  part  soluble  in  3 
parts  of  water  at  15°C. ;  almost  insoluble  in  boiling  water;  soluble  in 
1*37  parts  alcohol  at  15°C.  ;  almost  insoluble  in  boiling  alcohol.  In 
order  to  make  it  conform  to  the  text  under  ammonium  chloride  it 
should  read,  1  part  soluble  in  1*37  parts  of  boiling  water,  and  almost 
insoluble  in  alcohol  at  15°C. 
The  test  of  the  Pharmacopoeia  for  the  absence  of  lead  chromate  from 
lead  iodide  should  read  about  as  follows:  aOn  triturating  1  part  of  the 
salt  (lead  iodide)  with  2  parts  of  chloride  of  ammonium  in  a  porcelain 
mortar  and  adding  2  parts  of  water,  the  mixture  should  soon  change  to 
a  white  color  and  when  heated  should  dissolve  without  residue." 
THE  PREPARATION  OF  PURE  BENZOIC  ACID  FROM 
URINE.1 
By  T.  S.  Dymond. 
Contribution  from  the  Research  Fund  of  the  School  of  Pharmacy  Students1 
Association. 
In  the  production  of  some  glycocine  from  hippuric  acid,  for  the  con- 
firmation of  the  reported  synthesis  of  uric  acid,  the  results  of  which 
investigation  I  partly  brought  before  this  Association  last  year,  I 
obtained  as  a  bye-product,  benzoic  acid.  The  preparation  of  benzoic 
acid  in  this  way  is  interesting,  because  it  is  indirectly  obtained  from 
urine,  hippuric  acid  being  derived  from  that  source,  and  because  the 
use  of  such  benzoic  acid,  which,  as  hitherto  prepared,  retains  the  odor 
of  urine,  is  prohibited  by  British,  German  and  United  States  Pharma- 
copoeias. This  being  the  case,  I  have  made  a  few  experiments  to 
determine  in  what  way  benzoic  acid  thus  obtained  differs  from  that 
obtained  from  gum  benzoin. 
Preparation. — The  commercial  method  of  preparing  benzoic  acid 
from  urine  is  by  boiling  putrid  urine  (which  contains  the  hippuric  acid 
in  solution)  with  hydrochloric  acid.  A  purer  body  will  obviously  be 
obtained  at  little  more  expense  by  first  separating  the  hippuric  acid, 
and  this  now  is  frequently  done  commercially.  The  phosphates  in  the 
urine  taken  are  precipitated  by  lime.  The  urine  is  neutralized  with 
hydrochloric  acid,  and  evaporated  to  a  low  bulk.    Strong  hydrochloric 
1  Read  at  a  meeting  of  the  School  of  Pharmacy  Students'  Association, 
November  29,  1883. 
