Am;i°riir;i9oTrnJ'}    Recent  Literature  Relating  to  Pharmacy.  189 
VOLUMETRIC  ASSAY  OF  SALICYLIC  ACID. 
The  following  method  is  suggested  as  an  improvement  over  pro- 
cesses yet  devised.  Instead  of  using  bromine  acidulated  with  hydro- 
chloric acid,  potassium  bromide  is  employed.  This  is  treated  with 
an  exact  quantity  of  sodium  hypochlorite  solution,  titrated  to  rep- 
resent in  each  litre  3-55  grammes  of  chlorine,  8  grammes  of  bro- 
mine, and  3-45  grammes  salicylic  acid.  This  volumetric  solution 
will  keep  its  strength  for  about  a  month  if  kept  in  a  dark  place. 
The  details  of  the  assay  are  as  follows :  1  gramme  salicylic  acid  is 
dissolved  in  2  c.c.  solution  of  soda  and  50  ex.  water,  and  the  vol- 
ume brought  up  to  exactly  500  c.c.  by  addition  of  distilled  water. 
Twenty-five  c.c.  of  this  solution  is  put  into  an  Erlenmeyer  flask  of 
about  375  c.c.  capacity.  Five  c.c.  of  a  10  per  cent,  solution  of 
potassium  bromide  and  10  to  15  drops  of  hydrochloric  acid  are 
added,  and  to  this  mixture  is  poured  in  drop  by  drop  from  a  burette 
the  titrated  solution  of  hypochlorite,  until  one  drop  communicates 
a  distinct  but  feeble  yellow  color  to  the  mixture.  To  avoid  error 
it  is  better  to  have  a  layer  of  5  c.c.  chloroform  (with  sufficient  al- 
cohol to  prevent  emulsification  in  the  mixture)  to  receive  the  first 
suggestion  of  free  bromine.  When  this  yellow  is  reached,  the 
amount  of  cubic  centimetres  of  hypochlorite  employed  is  read,  and 
the  exact  amount  of  salicylic  acid  is  estimated  by  multiplying  by 
3-45.  The  same  method  can  be  utilized  for  estimation  of  the  sali- 
cylic acid,  and  also  for  phenol. — (F.  Telle,  J.  Ph.  et  Ch.y  190 1,  49.) 
H.  V.  A. 
OXIDIZING  ACTION  OF  AMMONIUM  PERSULPHATE. 
This  chemical  converts  uric  acid  in  the  cold  to  guanine,  ammo- 
nium allanturate,  ammonium  oxalate  and  urea.  It  changes  biliru- 
bine  in  alkaline  solution  to  biliverdine.  It  oxidizes  haematine  in 
ammoniacal  solution  in  the  cold,  and  more  rapidly  after  heating,  to 
a  colorless  liquid  in  which  is  found  a  precipitate  of  peroxide  of  iron. 
In  the  same  way  it  attacks  diluted  blood.  These  reactions  seem  to 
point  to  the  future  value  of  this  reagent  in  physiological  examina- 
tions.— (L.  Hugonenq,  J.  de  Ph.  et  Ck.,  1901,  64.)  H.  V.  A. 
DETECTION  OF  OIL  OF  SESAME  IN  OTHER  OILS. 
A  solution  of  100  parts  of  hydrochloric  acid  to  three  or  four  parts 
of  crystallized  glucose  is  prepared.    One  part  of  the  reagent  is  put 
