548 
ADULTERATION  OF  MEDICINES. 
Epsom  Salts. — There  is  a  large  quantity  of  a  spurious  article 
in  the  market,  which  is  nothing  more  than  finely  crystallized 
glauber  salt.  It  does  not  contain  a  trace  of  sulphate  of  mag- 
nesia. It  may  be  recognized  by  the  circumstance  that  it  is  per- 
fectly free  from  bitterness  to  the  taste,  and  that  its  aqueous 
solution  produces  no  precipitate  on  adding  first  phosphate  of  soda 
and  afterward  aqua  ammonia. 
Sal  Mochelle. — An  article  purporting  to  be  sal  rochelle  is  now 
offered  for  sale,  which  contains  at  least  25  per  cent,  of  sulphate 
of  soda.  This  can  be  discovered  by  adding  to  a  somewhat  dilute 
solution  of  the  suspicious  salt  a  few  drops  of  a  solution  of  either 
nitrate  of  baryta  or  chloride  of  barium,  and  afterward  c.  p. 
nitric  acid.  The  precipitate  produced  by  the  baryta  salt  must 
disappear  on  the  admixture  of  the  nitric  acid  if  the  salt  is 
pure. 
Vienna  Glycerin. — I  had  occasion  to  examine  this  really 
beautiful-looking  article,  and  found  it  contaminated  with  sul- 
phate of  lime  (gypsum)  and  chloride  of  sodium  (salt).  It  con- 
tained also  considerable  quantities  of  sugar. 
The  presence  of  the  sulphuric  acid  of  the  gypsum  can  easily  be 
made  manifest,  by  adding  to  one  sample  a  few  drops  of  a  baryta 
salt  solution,  and  afterwards  diluted  nitric  acid  ;  that  of  the 
lime,  by  admixing  to  another  sample  a  solution  of  oxalate  of 
ammonia.  The  chlorine  of  the  salt  is  discovered  by  the  appear- 
ance of  a  white  precipitate  on  the  addition  of  nitrate  of  silver 
solution. 
It  is  a  little  more  difficult  to  demonstrate  the  fradulent  ad- 
mixture of  sugar.  In  order  to  do  so,  it  is  necessary  to  add  about 
fifteen  or  twenty  drops  of  diluted  sulphuric  acid  to  two  or  three 
drachms  of  the  glycerin,  previously  diluted  with  its  own  bulk  of 
water.  This  mixture  is  boiled  over  the  spirit  lamp  for  several 
minutes,  when  it  is  allowed  to  cool  down.  It  is  then  mixed  with 
a  few  drops  of  a  solution  of  sulphate  of  copper,  and  as  much 
caustic  potassa  (liquor  potassa)  as  is  necessary  to  redissolve  the 
blue  precipitate  which  at  first  made  its  appearance.  The  whole 
is  then  gently  heated  over  the  spirit  lamp,  when  a  copious  brick- 
red  deposit  of  suboxide  of  copper  is  thrown  down.  Pure  gly- 
cerin will,  under  such  treatment,  not  produce  these  phenomena. 
