18 
Analysis  of  Malt  Extract. 
Am.  Jour.  Pharm. 
Jau.,  1885. 
This  solution  should  never  be  allowed  to  stand  longer  than  6  or  8 
hours,  and  during  this  time  should  be  kept  at  a  cool  place.  Further, 
every  time  the  solution  is  measured  or  weighed  it  should  be  well 
shaken. 
On  the  incineration  of  malt  extract,  a  charcoal  very  difficult  to  con- 
sume, is  produced,  and  it  is  therefore  best  to  incinerate  only  small 
quantities  ;  for  example,  5cc.  of  the  10  per  cent,  solution.  Complete 
combustion  may  be  attained  by  frequently  cooling  the  crucible,  damp- 
ening the  charcoal  with  alcohol  or  spirit  of  nitrous  ether  and  allowing 
the  temperature  never  to  exceed  a  dark  red  heat.  If  a  combustion- 
furnace  is  at  hand,  the  incineration  with  oxygen  is  to  be  preferred  to 
any  other  method. 
The  determining  of  the  several  constituents  of  the  ash  may  be 
omitted  here ;  but  I  would  remark,  that  the  amount  of  phosphoric 
acid  is  one-third,  and  that  of  potassa  is  30  to  32  per  cent,  of  the  whole 
ash. 
Estimation  of  the  Solids  and  of  the  Water. — If,  instead  of  using  the 
tables  published  in  my  former  article,  gravimetric  determinations  are 
to  be  made,  I  would  Ijke  to  call  attention  to  the  following: 
Evaporation  of  the  extract  by  the  usual  method  is  not  easily  accom- 
plished, as  notwithstanding  all  care,  the  extract  will  be  partly  burnt 
near  the  edge  of  the  crucible,  while  the  main  bulk  is  yet  damp.  To 
avoid  this  cliange  it  is  necessary  to  mix  the  extract  with  dry,  clean 
sand  and  expose  it  in  a  glass  tube  placed  in  the  drying-oven  to  a  cur- 
rent of  dry  air  or  carbonic  acid  gas.  In  this  manner  exact  results  are 
quickly  attained.  Should  the  extract  of  commerce  contain  glycerin, 
it  is  necessary  to  call  attention  to  the  fact  that  glycerin  may  lose  12 
per  cent,  of  its  weight  on  heating  at  110°C.  for  6  hours. 
Estimation  of  the  Nitrogenous  Substances. — In  estimating  these  sub- 
stances, combustion  with  soda-lime  should  always  be  resorted  to.  Or 
the  total  albumen,  etc.,  may  be  precipitated  with  tannin  solution.  The 
precipitate  is  then  washed,  dried,  weighed,  and  after  a  deduction  of 
8" 7 5  per  cent,  for  tannin,  is  counted  as  nitrogenous  substance. 
Another  part  of  the  solution  of  malt  is  boiled,  and  after  cooling,  the 
coagulated  albumen  is  collected,  washed,  weighed,  and  deducted  from 
the  total  albumen.  In  this  manner  we  get  the  amount  of,  by  heat, 
soluble  and  insoluble  albuminous  bodies.  In  both  estimations  the  ash 
should  also  be  determined  and  its  amount  deducted. 
Attention  should  also  be  directed  to  the  necessity  of  precipitating 
