'%lr-i8o'™- }  Chemical  Notes.  1 47 
moist  fibrin  in  slightly  acid,  neutral  or  slightly  alkaline  solution,  it  dis- 
solves large  quantities  of  that  substance,  the  fibrin  first  softening,  then 
disintegrating  without  swelling  and  dissolving,  leaving  a  residue  of 
dyspeptone.  The  above-mentioned  pulp,  even  after  careful  washing, 
f)resented  similar  characters. — Compt.  Rend..,  No.  89,  p.  425. 
Action  of  the  Sap  of  Carica  Papaya. — L.  Wittmak  finds  that  the  sap 
of  Carica  papaya  contains  a  ferment  analogous  to  pepsin,  from  which 
it  is  distinguished  by  its  acting  upon  milk  quickly  without  addition  of 
acid.  On  boiling  a  solution  of  the  sap,  or  on  adding  mercuric  chloride, 
iodine  or  mineral  acids,  a  precipitate  is  formed.  This  substance 
resembles  pepsin  in  being  precipitated  by  neutral  lead  acetate,  but  not 
by  potassium  ferrocyanide  or  ferric  chloride.  One  milligram  of  the 
'dried  sap  coagulated  10  cc.  of  milk  at  35°. — Journ.  Chem.  Soc.^  Nov., 
1879,  from  Bied.  Centr.^  p.  475. 
Change  of  Piperidina  into  Pyridin. — Within  the  last  few  years  pyri- 
din  derivatives  have  been  gotten  from  a  number  of  the  alkaloids,  as, 
for  example,  from  the  several  quinia  bases,  from  nicotina  and  from 
berberina.  W.  Koenigs  has  now  obtained  pyridin,  C^H^N,  from 
piperidina,  C^H^^N,  the  base  which  is  produced  at  the  same  time  with 
piperic  acid  by  the  decomposition  of  the  alkaloid  piperin.  This 
change  was  effected  by  heating  the  piperidina  for  some  hours  with  an 
excess  of  sulphuric  acid  to  about  300°C.  During  the  process  a  steady 
evolution  of  sulphurous  acid  gas  took  place,  but  no  coaking  was  observed. 
The  base  extracted  with  ether,  and  purified,  was  converted  into  the 
platinum  double  salt,  and  analyzed. — Ber..,  xii,  p.  2341. 
Action  of  Potassium  Ferricyanide  upon  Morphia. — Polstorff  has  exam- 
ined the  product  of  the  oxidation  of  morphia  by  potassium  ferricyanide, 
and  has  obtained  a  well-crystallized  very  stable  base  of  the  composi- 
tion C3^H3gN20^.  This  he  names  oxydimorphia,  considering  that  it 
has  formed  by  the  elimination  of  one  atom  of  hydrogen  from  each  of 
two  molecules  of  morphia,  Cj.H^gNOg,  and  the  linking  together  of  the 
C.,H,3N03 
•residues,  thus :    |  He  prepared  and  analyzed  the  sulphate 
and  the  chlorhydrate  of  this  base. — Ibid..,  xiii,  p.  86. 
Other  Methods  of  Formation  of  Oxydimorphia. — Polstorff  and  Broock- 
mann  have  also  repeated  Schiitzenberger's  (^'Bul.  de  la  Soc.  Chim.," 
1865,  No.  4,  p.  176)  preparation  of  oxymorphia  by  the  action  of  silver 
nitrate  upon  morphia  hydrochlorate,  and  find  that  the  base  so  obtained 
