480 
Peptone  Salts  from  Glutin. 
/  Aru.  Jour.  Pharm. 
I       Sept.,  \W&. 
glutin  in  presence  of  very  dilute  hydrochloric  acid,  a  peptone  salt  is 
also  obtained  which  closely  resembles  the  salt  last  described,  but  is 
not  completely  soluble  in  cold  methyl  alcohol  ;  it  is  separated  by 
dialysis  into  two  fractions,  one  of  which  contains  2*97  per  cent. 
HQ,  and  is  almost  insoluble  in  methyl  alcohol,  whilst  the  other 
contains  11-13  Per  cent.  HQ. 
In  all  cases  it  appears  that  the  salts  formed  either  by  the  action  of 
acid  or  of  pepsin  and  acid  are  separable  into  two  portions  containing 
a  maximum  and  minimum  percentage  of  acid,  and  it  therefore 
appears  probable  that  the  molecule  of  glutin  contains  two  atom- 
complexes,  which  in  the  first  stage  of  the  reaction  yield  two  separate 
molecules.  These  differ  greatly  in  the  resistance  they  offer  towards 
further  change,  the  one  which  forms  salts  containing  a  larger  quan- 
tity of  acid,  being  more  readily  converted  into  its  ultimate  products 
of  decomposition,  namely,  the  amido-acids. 
The  acid  in  the  giutinpeptone  salts  is  very  firmly  combined,  and 
great  difficulty  was  experienced  in  converting  the  salts  into  the 
free  peptones.  This  was  first  accomplished  by  adding  a  large 
excess  of  alkali  and  removing  the  inorganic  substances  by  dialysis, 
but  great  loss  of  substance  also  takes  place.  It  was  then  found 
that  the  change  may  be  brought  about  quantitatively  by  adding  a 
slight  excess  of  pure  silver  sulphate,  filtering  from  silver  chloride, 
removing  the  excess  of  silver  with  hydrogen  sulphide,  and  the  sul- 
phuric acid  with  the  necessary  amount  of  baryta-water.  The 
glutinpeptones  thus  obtained  are  soluble  in  all  proportions  in  water, 
but  insoluble  in  alcohol  and  ether ;  their  aqueous  solutions  have  an 
acid  reaction  towards  litmus,  but  do  not  turn  Congo  paper  blue. 
On  analysis,  it  was  found  that  the  percentage  of  carbon  was  rather 
less,  and  that  of  hydrogen  rather  more,  than  in  the  case  of  glutin; 
this  is  in  complete  agreement  with  the  supposition  that  they  are 
products  of  hydrolysis. 
Attempts  were  also  made  to  determine  the  molecular  weights  of 
these  substances  by  the  cryoscopic  method  in  aqueous  solution  and 
by  the  boiling-point  method  in  aqueous  and  methyl  and  ethyl  alco- 
holic solution.  The  results  show  that  the  molecule  of  peptone  salt 
becomes  smaller  as  the  percentage  of  acid  increases  ;  further,  that 
the  salts  are  dissociated  in  aqueous  and  methyl  alcoholic  solutions, 
but  not  in  ethyl  alcoholic  solution,  for  the  molecular  weight  deduced 
from  the  boiling  point  of  the  solutions  in  the  last  solvent  is  double 
