Am.  Jour.  Pharni.  ) 
Aug.,  1885.  j 
Gleanings  from  Foreign  Journals. 
383 
bidity  disaj^pearing  while  shaking.  On  boiling  this  sohition  all  the 
oxide  of  cadmium  is  precipitated  while  the  copper  is  retained  in  solu- 
tion. The  white  Cd  (OH)2  which  settles  rapidly,  is  collected,  washed 
with  a  little  water  and  dissolved  in  NH^OH,  and  this  ammoniacal 
solution,  treated  with  ammonium  sulphide  or  H2S,  gives  the  charac- 
teristic yellow  precipitate  of  CdS.  Ammoniacal  salts  prevent  precipi- 
tation; in  this  case  the  solution  of  the  tartrate  is  rendered  strongly 
alkaline  and  then  boiled,  when  the  ammonia  escapes  and  the  precipitate 
is  formed. — Rep.  de  Fhai-m.,  No.  6,  1885. 
Quantitative  Valuation  of  Resin  in  Soap. — The  method  is  based 
upon  the  behavior  of  NaCl  to  separate  out  of  a  solution  of  soap,  only 
the  fat  soap,  while  the  resin  soap  is  retained  in  solution.  Dr.  Heiner's 
experiments  made  with  soap  containing  20  per  cent,  of  resin,  gave  on 
an  average  per  cent,  less  of  resin.  Two  samples  of  equal  weight 
are  treated  ;  one  is  decomposed  with  H2SO4,  and  the  fatty  acids  con- 
taining the  resin  are  weighed.  Dissolve  the  other  sample  in  water, 
treat  with  solution  of  NaCl,  separate  the  liquid  containing  the  resin 
and  glycerin  from  the  soap- mass,  wash  with  solution  of  NaCl,  dissolve 
again  in  water,  precipitate  again,  wash  repeatedly  with  the  salt  solution, 
and  decompose  the  pare  soap  with  HgSO^,  and  weigh.  The  difference 
in  weight  of  the  two  results  gives  the  w^eight  of  resin. — 3Ionit.  Scientif.  ; 
Centralhalle,  No.  25,  1885. 
Detection  of  cane  sugar  in  sugar  of  milk. — If  a  mixture  of  equal 
parts  of  oxalic  acid  and  sugar  of  milk  be  warmed  over  the  water-bath, 
the  mass  melts  and  assumes  a  faintly  darker  coloration  on  being  heated 
for  some  time.  In  case  the  mixture  contains  but  one  per  cent,  of  cane 
sugar,  it  darkens  very  rapidly,  changing  from  greenish  brown  to  black 
in  the  presence  of  a  larger  percentage  of  cane  sugar.  This  method  was 
first  proposed  by  Lorin  in  ^'  Ph.  Zeitsch.  f.  Russland,"  xvii,  372,  and  is 
recommended  as  a  reliable  one  in  "  Phar.  Centralh.,^'  No.  22,  1885, 
p.  244. 
Estimation  of  milk  sugar  and  cane  sugar. — The  method  of  A.  W. 
Stokes  and  R.  Bodmer  is  especially  adapted  for  milk,  and  requires  an 
ammoniacal  Fehling's  solution,  prepared  as  follows :  Dissolve  crys- 
tallized sulphate  of  copper  34*65,  Rochelle  salt  170,  liquor  potassse 
170,  in  sufficient  water  to  make  one  liter.  To  120  cc.  of  this  solution 
add  400  cc.  ammonia  (spec.  grav.  0*880),  and  dilute  to  one  liter.  This 
amnioniated  cupric  fluid  constitutes  the  Pavy  solution,  of  which  10  cc. 
correspond  to  0*005  Gm.  of  glucose;  it  is  advisable  to  standardize  it 
