354  PREPARATION  OF  SUCCINIC  ACID  FROM  MALATE  OF  LIME. 
pure  acid,  1  drm.  of  oleum  succini  rectification  is  added  to  every 
pound  of  the  dry  acid,  mixed  with  it  most  intimately  by  tritura- 
tion, and  again  sublimed.  The  product  of  the  sublimation,  or 
the  mixture  of  oil  and  acid,  is  dissolved  in  2  parts  of  boiling- 
water,  filtered,  and  set  to  crystallize.  To  procure  chemically 
pure  acid,  the  whitest  is  selected,  and  treated  in  the  known  man- 
ner. 
From  the  preceding  statements  it  appears  that  the  officinal  acid 
may  also  be  obtained  directly  by  the  simple  sublimation  of  the 
crude  acid  impregnated  with  the  oil  of  amber. 
Pure  succinic  acid  is  obtained  from  the  crude  product  in 
crystals  similar  to  those  of  sulphate  of  quinine.  The  retort  is 
immersed  in  the  sand  not  deeper  than  it  is  filled  with  the  mixture 
of  succinic  acid  with  a  little  sulphuric  acid.  This  must  not  fill 
more  than  one-fourth  of  the  retort.  As  soon  as  the  dome  and 
the  entrance  of  the  neck  of  the  retort  are  covered  with  beautiful 
dendritic  crystals,  which,  however,  must  reach  down  nearly  to 
the  middle  of  the  retort,  it  is  allowed  to  cool  slowly.  The  whole 
belly  of  the  retort  is  then  found  filled  with  this  beautiful  pre- 
paration down  to  the  solidified  unsublimed  portion.  The  retort 
is  destroyed,  as  the  lower  portion,  containing  the  fused  crude 
acid,  must  be  broken  away  in  order  to  procure  the  crystalline 
acid,  which,  when  spread  upon  bibulous  paper,  is  heated  to  expel 
the  sulphurous  acid  and  moisture. 
The  process,  according  to  the  author's  experience,  is  the  short- 
est and  most  certain.  The  purification  of  the  crude  acid  by  re- 
peated crystallization,  and  decoloration  by  pure  animal  charcoal, 
takes  up  a  great  deal  of  time  and  causes  a  considerable  loss ;  in 
the  first  case  the  crystals  always  become  covered  with  a  somewhat 
resinous  coat,  which  spoils  their  appearance,  and  can  scarcely  be 
got  rid  of  without  the  employment  of  animal  charcoal. 
5.  Metamorphoses  of  Malate  of  Lime. — It  is  of  great  import- 
ance that  all  sugar  should  be  washed  out  of  the  malate  of  lime 
before  it  is  exposed  to  fermentation.  If  the  salt  contain  sugar, 
it  produces  first  of  all  lactate  of  lime,  and,  according  to  the 
duration  of  the  process,  and  the  mode  in  which  it  is  carried  on, 
metacetonate,  butyrate,  and  acetate  of  lime. 
In  the  complete  conversion  of  malate  into  succinate  of  lime, 
the  only  subordinate  products  are  carbonate  and  acetate  of  lime. 
