78 
Peptone, 
/  Am.  Jour.  Pharm. 
\      Feb.,  1881. 
It  is,  then,  established  that  the  papaine  commences  by  fixing  itself 
upon  the  fibrin,  and  that  the  insoluble  product,  perhaps  a  combination 
of  the  fibrin  and  the  papaine,  gives  by  the  action  of  water  the  soluble 
products  of  hydration  of  the  fibrin,  at  the  same  time  the  ferment  being 
again  set  free  can  exercise  its  action  on  a  new  portion  of  fibrin. 
This  action  will  thus  be  found  to  recall  that  of  the  chemical  agents, 
properly  speaking,  sulphuric  acid,  for  example,  small  quantities  of 
which  can  exercise  a  hydrating  action,  in  consequence  of  the  ephem- 
eral formation  of  combinations  which  are  produced  and  resolved 
without  cessation. 
PEPTONE. 
By  C.  a.  Pekelharing, 
The  researches  of  Plosz,  Malay,  and  Adamkiewicz,  the  author 
admits,  point  to  the  conclusion  that  albuminoids,  although  changed  by 
the  digestive  fluids  into  peptones,  resume  after  absorptioon  their  ori- 
ginal properties,  and  further,  that  peptone  may  be  substituted  for 
albuminoids,  as  a  food  not  only  without  harm,  but  with  positive 
advantage  to  the  animal.  But  it  is  obvious  from  the  methods  of  pre- 
paration of  peptone  adopted  by  these  observers,  that  the  word  "  pep- 
tone "  has  not  the  clear  and  definite  meaning  usually  attributed  to  it. 
The  method  used  in  all  these  cases  was  the  digestion  of  fibrin  by  gas- 
tric juice.  But  the  times  deemed  sufficient  by  each  observer  for  com- 
plete conversion  vary  widely.  Plosz,  2  to  3  weeks ;  Malay,  2  to  3  days ; 
Adamkiewicz,  2  to  5  hours.  Despite  these  differences,  the  conclusions 
arrived  at  agree  in  the  main,  viz.,  that  peptone  can  replace  proteids 
as  food,  and  that  animals  so  fed  will  not  only  maintain,  but  increase 
their  weight. 
After  examining  these  results  more  in  detail,  the  author  remarks  on 
the  importance  of  experimenting  with  a  substance  of  constant  compo- 
sition, and  proceeds  to  describe  his  method  of  preparing  pure  peptone, 
which  depends  on  a  property  described  by  Place  and  Huizinga  On- 
derzoekingen  gedaan  in  het  physiologisch  laboratorium  der  Leidsche 
Hoogeschool,''  1870,  and  Maandblad  von  Naturwetenschappen,^' 
1873,  p.  29),  viz.,  that  in  the  cold  a  solution  of  peptone,  having  an 
acid  reaction,  is  precipitated  by  neutral  salts,  the  precipitate  redissolv- 
ing  on  warming. 
Fibrin  from  bullock's  blood  and  egg-albumin  was  used,  and  was 
digested  with  0*2  per  cent,  hydrochloric  acid,  and  pepsin  (either  com- 
