﻿506 
  Mr. 
  W. 
  Sutherland 
  : 
  Another 
  Method 
  of 
  

  

  the 
  presence 
  of 
  C 
  and 
  H 
  groups, 
  which 
  for 
  the 
  trivalent 
  ion 
  

   in 
  peptones 
  give 
  HCCH 
  2 
  COO(CHNH 
  2 
  COO) 
  2 
  as 
  a 
  typical 
  

   formula, 
  having 
  B 
  = 
  144. 
  The 
  actual 
  formula 
  must 
  he 
  

   decided 
  by 
  chemical 
  analysis 
  of 
  the 
  acid 
  ions 
  when 
  separated 
  

   from 
  the 
  residue. 
  But 
  as 
  regards 
  the 
  two 
  peptones 
  yielding 
  

   trivalent 
  ions 
  we 
  can 
  assert 
  that 
  the 
  molecular 
  mass 
  of 
  

   pepsinfibrinpeptone 
  a 
  must 
  be 
  a 
  multiple 
  of 
  515, 
  the 
  minimum 
  

   possible 
  by 
  analysis, 
  and 
  also 
  a 
  multiple 
  of 
  three 
  times 
  24:8, 
  

   the 
  equivalent 
  found 
  by 
  electric 
  titration. 
  The 
  smallest 
  

   number 
  which 
  satisfies 
  these 
  conditions 
  within 
  the 
  limits 
  

   of 
  experimental 
  error 
  in 
  determining 
  the 
  equivalent 
  is 
  

   515x3 
  = 
  1545, 
  which 
  would 
  give 
  an 
  equivalent 
  of 
  257, 
  the 
  

   experiments 
  giving 
  a 
  possible 
  range 
  from 
  234 
  to 
  262. 
  In 
  

   the 
  same 
  way 
  the 
  molecular 
  mass 
  of 
  pepsinglutin 
  peptone 
  

   must 
  be 
  a 
  multiple 
  of 
  573 
  and 
  also 
  of 
  3x 
  320. 
  In 
  this 
  case 
  

   5 
  X 
  573 
  satisfies 
  the 
  conditions, 
  since 
  2865/9 
  gives 
  an 
  equi- 
  

   valent 
  of 
  317, 
  while 
  the 
  experimental 
  range 
  is 
  from 
  317 
  to 
  

   328. 
  Treating 
  the 
  divalent 
  ions 
  in 
  the 
  same 
  way, 
  we 
  find 
  

   for 
  the 
  ion 
  of 
  trypsinfibrinpeptono 
  a 
  such 
  a 
  formula 
  as 
  

   (CHNH 
  2 
  ) 
  4 
  (COO) 
  2 
  ; 
  for 
  which 
  B 
  is 
  152 
  instead 
  of 
  150, 
  and 
  

   for 
  pepsinfibrinpeptone 
  ft 
  ions 
  the 
  formula 
  C(NH 
  2 
  ) 
  2 
  (COO) 
  2 
  , 
  

   for 
  which 
  B 
  is 
  80 
  instead 
  of 
  83. 
  For 
  a. 
  the 
  molecular 
  mass 
  

   is 
  to 
  be 
  a 
  multiple 
  of 
  259, 
  and 
  also 
  of 
  2 
  x 
  157. 
  The 
  number 
  

   1295 
  is 
  the 
  lowest 
  satisfying 
  the 
  conditions 
  nearly, 
  since 
  

   1295/8 
  gives 
  an 
  equivalent 
  162, 
  the 
  experimental 
  value 
  

   ranging 
  from 
  157 
  to 
  164. 
  For 
  the 
  ft 
  form 
  the 
  molecular 
  

   mass 
  is 
  a 
  multiple 
  of 
  273, 
  and 
  also 
  of 
  2 
  x 
  197, 
  and 
  2730 
  

   meets 
  the 
  case. 
  We 
  have 
  not 
  obtained 
  perfectly 
  definite 
  

   molecular 
  masses 
  for 
  the 
  peptones, 
  because 
  we 
  have 
  found 
  

   that 
  we 
  really 
  deal 
  only 
  with 
  the 
  acid 
  ions 
  split 
  from 
  the 
  

   peptone 
  molecule, 
  and 
  are 
  without 
  definite 
  experimental 
  

   information 
  as 
  to 
  the 
  mass 
  of 
  the 
  neutral 
  residue. 
  The 
  HC1 
  

   compounds 
  of 
  peptone 
  are 
  not 
  so 
  definite 
  in 
  their 
  behaviour 
  

   as 
  the 
  NaOH 
  compounds, 
  so 
  that 
  Neumann's 
  experiments 
  

   with 
  them 
  do 
  not 
  enable 
  us 
  to 
  add 
  anything 
  of 
  importance 
  

   to 
  the 
  foregoing. 
  The 
  molecular 
  mass 
  of 
  the 
  peptones 
  seems 
  

   to 
  be 
  of 
  the 
  order 
  1400 
  or 
  2800. 
  If 
  we 
  use 
  the 
  estimated 
  

   molecular 
  masses 
  for 
  the 
  four 
  peptones 
  along 
  with 
  the 
  masses 
  

   of 
  the 
  ions 
  in 
  M. 
  = 
  n 
  2 
  p 
  + 
  r 
  £° 
  r 
  calculating 
  r, 
  we 
  get 
  the 
  values 
  

   1111, 
  2214, 
  479, 
  and 
  1806. 
  Apparently 
  these 
  residues 
  are 
  

   important 
  substances 
  still 
  of 
  considerable 
  complexity. 
  

  

  In 
  this 
  connexion 
  it 
  will 
  be 
  useful 
  to 
  consider 
  briefly 
  the 
  

   molecular 
  conductivities 
  of 
  aqueous 
  solutions 
  of 
  the 
  peptones 
  

   found 
  by 
  Neumann, 
  these 
  being 
  calculated 
  by 
  him 
  according 
  

   to 
  Siegfried's 
  formulae 
  above, 
  as 
  if 
  these 
  gave 
  correct 
  mole- 
  

   cular 
  masses. 
  I 
  find 
  that 
  his 
  results 
  can 
  be 
  expressed 
  by 
  

  

  