216 
Chemical  Notes. 
(  Am.  Jour.  Pharm. 
I      May,  1882, 
this  purpose  a  zinc  plate  is  hung  in  a  copper  solution,  where  it 
soon  becomes  covered  Avith  metallic  copper,  and  acquires  the  property 
of  dissolving  with  formation  of  zinc  hydrate  and  liberation  of  hydro- 
gen. If  such  an  element  is  brought  in  contact  with  dilute  alcoholic 
solutions,  of  say  40  to  60  per  cent.,  there  is  immediate  absorption  of 
the  liberated  hydrogen,  and  the  characteristic  unpleasant  odor  of  the 
(Tude  alcohol  solution  disappears  quite  rapidly.  If  now  the  solution 
1)6  distilled  there  is  obtained  a  yield  of  alcohol  25  to  30  per  cent, 
greater  than  by  the  previous  methods,  and  much  better  tasting.  For 
the  technical  details  of  this  important  method  reference  must  be  had 
to  the  original  communication. — Bull,  de  la  Soc.  Chim.,  36,  p.  273. 
Preparation  of  Lactic  Acid. — H.  Kiliani  has  made  the  important 
announcement  that  lactic  acid  may  be  readily  prepared  by  the  action 
of  potassium  or  sodium  hydrate  upon  both  grape  sugar  and  invert 
sugar,  or  cane  sugar,  after  treatment  with  dilute  acids. 
In  his  first  paper  he  gives  the  following  directions :  Dissolve  one 
part  of  grape  sugar  in  one  part  of  water,  and  then  one  part  of  potas- 
sium hydrate  in  one-half  part  water.  The  cooled  solutions  are  mixed 
in  such  proportion  that  for  every  10  grams  of  sugar  10  cb.  cm.  of  pot- 
ash solution  is  used.  In  working  with  larger  amounts  the  alkali  must 
be  added  slowly  and  with  constant  cooling.  The  mixture  is  then 
warmed  for  several  hours  in  a  stoppered  flask  to  about  35°C.,  and 
then  allow  the  temperature  to  rise  gradually  to  60°C.,  and  digest  until 
the  solution  no  longer  reduces  Fehling's  solution.  This  will  ordina- 
rily take  from  6  to  7  hours,  heating.  In  the  meantime  determine  by 
simple  titration  how  much  of  a  very  concentrated  sulphuric- acid 
(3  parts  pure  acid  and  1  part  water)  is  needed  to  neutralize  a  given 
amount  of  the  alkali  used  in  the  above  experiment.  After  the  cool- 
ing down  of  the  mixture  in  the  flask  a  sufficient  amount  of  sulphuric 
acid  is  then  added  to  neutralize  the  alkali  that  had  been  used.  While 
the  sulphuric  acid  is  being  added  potassium  sulphate  separates  out, 
and  the  liquid,  at  first  reddish-brown,  becomes  clearer  in  color  as  it 
becomes  acid.  It  is  then  concentrated  somewhat,  and  93  per  cent, 
alcohol  is  added,  with  stirring,  until  a  test  filtered  ofl"  remains  clear  with 
barium  chloride.  The  filtered  alcoholic  solution  is  warmed  over  the 
water-bath  with  carbonate  of  zinc  that  has  been  rubbed  up  with  water 
to  a  thick  paste,  and  then  filtered  boiling  hot.  If  too  much  alcohol  had 
not  been  added  previously,  on  cooling  the  filtrate  solidifies  to  a  magma 
of  zinc  lactate  that  is  made  pure  by  a  single  recrystallization.  The 
