Am.  Jour.  Pharm. 
Jan.,  1885. 
Analysis  of  3falt  Extract. 
19 
with  tannin  J  always  in  the  cold,  because,  if  the  sohitions  are  warm,  the 
resuhing  precipitate  cannot  be  filtered  off. 
The  coagulable,  and  while  boiling,  non-coagulable  nitrogenous  sub- 
stances are  the  most  important  estimations. 
For  the  separation  of  all  the  nitrogenous  bodies  I  recommend  W. 
Klinkenberg's  method,  published  in  "Repert.  d.  Analyt.  Chemie,"  II, 
376,  and  "Fresenius  Zeitschrift,"  vol.  22,  page  621.  I  have  made  a 
number  of  assays  according  to  this  method  and  received  good  results. 
A  malt  which  is  rich  in  diatase  contains  in  100  parts  of  nitrogenous 
substances: 
peptone   74*79 
albumin  47-14 
protein   8*07 
or,  coagulable  substance   37*70 
non-coagulable  substance   62*30 
With  respect  to  the  peptone,  the  greatest  variation  occurs,  and 
depends  on  the  greater  or  smaller  diastatic  action,  and  it  seems  also  to 
be  much  influenced  by  the  temperature  and  time  used  in  the  preparing 
of  the  malt  extract. 
Determination  of  the  Gum. — It  should  be  remarked  at  the  outset, 
that  a  malt  extract,  rich  in  diastase,  never  contains  a  trace  of  dextrin, 
but  a  gum  which  is  left  rotating,  and  therefore  does  not  deserve  the 
name  dextrin ;  it  is  precipitated  by  acetate  and  by  basic  acetate  of  lead, 
as  well  as  by  alcohol,  does  not  reduce  copper  solution  in  the  cold, 
but  on  heating,  reduces  it  only  very  slowly;  with  a  mixture  of  cal- 
cium chloride  and  ammonia  a  precipitate  is  produced.  It  is  easily 
transformed  into  right  rotating  sugar,  by  hydrochloric  or  sulphuric 
acid,  and  a  portion  of  it  is  also,  in  a  dilute  solution,  by  diastase,  con- 
verted into  dextro-sugar,  which  shows  the  presence  of  two  gums. 
If  malt  extract  be  allowed  to  act  on  a  large  amount  of  starch,  as  in 
the  production  of  maltose,  then  little  gum  and  a  large  quantity  of 
dextrin  is  produced.  Having  made  a  full  examination  of  this  gum,  I 
shall  report  my  results  in  a  subsequent  paper. 
For  the  determination  of  this  gum,  the  albuminous  bodies  are  pre- 
cipitated with  a  10  per  cent,  tannin  solution;  the  filtrate  is  then  mixed 
with  an  equal  volume,  or  a  sufficient  quantity  of  a  30  per  cent,  acetate 
of  lead  solution,  and  the  precipitate  is  washed  first  with  water,  and  later 
on  with  alcohol.  If  polarization  is  intended,  the  precipitate  may  be 
decomposed  by  sulphate  of  sodium,  and  the  clear  filtrate  brought 
