Am.  Jour.  Phann. ) 
April,  1881.  j" 
Peptones. 
185 
other  ingredients  successively  with  constant  trituration.  This  emulsion 
contains  thirty-three  per  cent,  of  castor  oil,  and  is  consequently  more 
limpid  than  the  fifty  per  cent,  codliver  oil  emulsions  above  described, 
and  is  in  every  respect  an  elegknt  preparation. 
JLouisville. 
PRESENCE  OF  PEPTONES  IN  PLANTS. 
By  E.  SCHUIiZE  AND  J.  Barbieri. 
As  Gorup-Besanez  has  demonstrated  the  existence  of  albumin  solvent 
ferments  in  the  seeds  and  other  parts  of  plants,  the  presence  of  peptones 
was  to  be  expected ;  but  experiments  with  a  view  of  finding  these 
substances  have  for  the  most  part  been  unsatisfactory.  On  the  one 
hand,  K.ern  has  found  peptones  in  the  extracts  of  fodder  plants,  lucerne, 
vetches,  etc.,  but  considers  that  they  were  formed  during  the  prepara- 
tion of  the  extracts.  On  the  other  hand,  Kellner  maintains  that 
peptones  are  neither  present  nor  are  formed  during  the  process  of 
extraction,  if  sufficient  care  be  taken.  The  authors  have  re-examined 
the  question  by  the  light  which  the  researches  of  Hofmeister  have 
thrown  on  the  chemical  nature  and  properties  of  peptones ;  they  have 
also  adopted  the  methods  of  separation  ("Abstr./'  1879,  183)  and  the 
so-oalled  biuret  reaction  {i.  e.,  red-violet  coloration  with  copper  sul- 
phate in  alkaline  peptones)  proposed  by  Hofmeister.  This  latter 
reaction  forms  a  basis  for  a  colorimetric  determination  of  peptone,  a 
number  of  solutions  of  standard  tints  being  prepared  by  dissolving 
known  weights  of  peptone  (from  blood  fibrin),  and  adding  to  them 
known  volumes  of  soda  and  copper  sulphate  solutions.  In  order  to 
isolate  peptone  from  vegetable  extracts,  the  authors,  adopting  the 
method  of  Rittliausen,  have  treated  the  albuminous  substance  known 
as  conglutin  (obtained  from  lupines)  with  pepsin  solution,  and  purified 
the  product  by  the  processes  used  for  fibrin  peptone.  This  prepara- 
tion was  not  so  pure  as  ordinary  fibrin  peptone,  resembling  the  latter 
in  its  behavior  towards  tannin  and  phosphotungstic  acid,  but  differ- 
ing from  it  in  giving  a  precipitate  with  acetic  acid  and  potassium  ferro- 
cyanide.  The  coloration  produced  from  the  plant-extract  with  copper 
sulphate  was  of  the  same  tint  as  that  formed  with  the  solution  of  fibrin 
peptone  of  strength  1  :  1,000.  Similar  results  were  obtained  with 
other  extracts,  and  the  authors  have  thus  demonstrated  the  existence 
of  p(';)ton('  in  plant-buds,  seeds,  potatoes  of  various  species,  and  in  the 
