454  Nitrogenous  Substances  in  the  Gastric  Juice.     { ^™sepri885 
molybdic  acids  give  a  green  color,  changing  to  blue,  brown  and  black. 
Selenic  and  sulphuric  acids,  sfter  a  time,  give  a  pale-green,  which  changes 
on  warming,  to  a  red-brown.  Sulphuric  acid  and  potassium  dichro- 
mate  give  similar  reactions.  Vanadic  sulphate  gives  an  intense 
emerald-green  coloration,  which  turns  to  a  bright  blue,  changing  to  a 
dark  green.  Potassium  nitrate  and  sulphuric  acid  give  a  green,  chang- 
ing to  a  blue,  and  finally  becomes  fawn-colored  (in  small  quantities, 
the  color  is  steel-blue).  Bromine  and  sulphuric  acid  give  a  red-brown 
with  green  streaks.  Sugar  and  sulphuric  acid  give  a  rose- violet  color, 
changing  to  cherry-red  and  blue- violet.  Chelidonine  is  not  extracted 
from  an  acid  solution  by  light  petroleum,  only  slightly  by  benzene, 
but  better  by  chloroform. — Jour.  Chem.  Soc,  May,  1885,  p.  608  ;  Zeit, 
Anal.  Chem.,  vol.  24,  165-166. 
NITROGENOUS  SUBSTANCES  INSOLUBLE  IN 
GASTRIC  JUICE. 
By  a.  Stutzer. 
In  almost  all  vegetables  there  are  found  three  groups  of  nitrogenous 
substances:  one,  soluble  in  water,  and  represented  by  asparagin ;  the 
second,  comprising  albumin,  dissolved  by  the  hydrochloric  acid  pepsin 
of  the  stomach,  and  chemically  distinguished  from  amides  by  forming 
insoluble  compounds  with  copper  hydroxide  in  neutral  solutions ;  the 
third  group  is  composed  of  all  those  nitrogenous  substances  which  are 
not  soluble  in  water  or  in  acid  pepsin.  The  author  undertook  the 
examination  of  the  latter  group,  and  as  the  results  of  experiments  on 
the  living  animal  would  probably  be  rendered  doubtful  by  the  presence 
of  mucin  and  other  nitrogenous  matters  in  the  excreta,  due  to  the 
transformation  of  tissue,  he  decided  on  employing  artificial  digestion. 
The  substance  used  for  preliminary  experiments,  was  commercial  cocoa- 
nut  cake,  largely  used  as  cattle  fodder.  This  was  treated  with  acid 
pepsin  solution,  and  afterwards  with  variously  prepared  extracts,  of 
pancreas,  in  order  to  remove  the  nitrogen  as  much  as  possible.  The 
results  showed  that  the  alkaline  pancreatic  extract  had  less  effect  on 
protein  matters  than  the  acid  pepsin,  although  in  some  cases  the  results 
were  very  close.  The  examination  of  other  animal  secretions  sug- 
gested itself  to  the  author.  Hoppe-Seyler  denies  the  power  of  intes- 
tinal secretions  to  dissolve  albumin,  and  even  should  it  be  proved  here- 
