^"Ap?n'^"i88r°™"}    Analytical  Researches  and  Investigations.  161 
yellowish  color,  while  concentrated  hydrochloric  acid  forms  a  nearly 
<5olorless  solution. 
^.  ^e7i;cO^  (freshly  rectified  and  boiling  at  from  80  to  81^0.)  takes 
up  only  very  small  quantities  of  a  resinous  substance,  which  in  its 
behavior  toward  the  above-mentioned  acids  resembles  that  obtained 
fr«m  the  petroleum  ether  solution,  and  which,  when  dissolved  in 
-dilute  sulphuric  acid  (1:50)  gives  no  precipitate  with  the  ordinary 
alkaloidal  reagents — iodine  and  bromine  solution,  potassio-mercuric 
and  potassio-cadmic  iodides;  gold,  platinum,  ferric  and  mercuric  chlo- 
rides; picric  and  tannic  acids,  and  potassium  bichromate — and  does  not 
reduce  chloride  of  gold  upon  warming.  Phosphomolybdic  acid  pro- 
duces only  after  standing  for  some  time  a  very  slight  turbidity.  This 
substance  also  possesses  but  a  feebly  bitter  taste. 
3.  Chloroform  corresponds  in  its  behavior  to  benzol. 
B.  Absorbed  frorfi  the  ammoniacal  solution.^ 
1.  Petroleum  ether  takes  up  little  or  nothing. 
2.  Benzol  removes  but  traces  of  a  substance,  which  occasionally 
-crystallizes  from  the  etherial  solution,  but  which  gives  no  characteristic 
color  or  physiological  reactions  similar  to  those  of  strychnine,  atropine, 
hyoscyamine,  etc. 
If  the  beer  has  become  sour  before  being  examined,  it  will  show  a 
similar  behavior  upon  agitation  with  these  liquids,  but  from  the  prop- 
erly prepared  acid  liquid  a  substance  will  be  extracted  (in  small  amount) 
by  benzol  and  chloroform  which,  upon  warming,  reduces  chloride  of 
gold,  and  usually  also  nitrate  of  silver.  Beer  worts  shows  the  same 
behavior  as  fermented  beer. 
In  regard  to  the  special  reactions  of  the  individual  bitter  principles, 
;as  also  of  the  alkaloids  which  here  come  under  consideration,  and 
which  may  be  isolated  according  to  the  above  method  and  subsequently 
recognized,  reference  must  be  made  to  the  original  essay,  or  to  Dragen- 
dorff's  Gerichtlich-chemisclie  Ermittelung  von  Giften,"  where  most 
of  the  detailed  reactions  have  been  previously  published. 
Glycerin  is  determined,  according  to  Y .  Griessmayer,  by  evaporating 
100  cc.  of  beer  in  a  shallow  capsule  on  the  water-bath,  as  slowly  as 
possible,  and  at  a  temperature  of  from  65  to  75 °C.  After  the  dissipa- 
tion of  the  carbonic  acid  gas  about  5  grams  of  magnesium  hydrate  are 
added,  and  the  mixture  repeatedly  stirred  with  a  glass  rod  so  that 
\Before  rendering  the  liquid  alkaline  it  should  again  be  shaken  with 
petroleum  ether  in  order  to  remove  the  last  portions  of  chloroform. 
11 
