﻿508 
  Mr. 
  W. 
  Sutherland 
  : 
  Another 
  Method 
  of 
  

  

  with 
  NaOH. 
  The 
  phenomena 
  of 
  diffusion 
  with 
  peptones 
  and 
  

   their 
  compounds 
  must 
  be 
  considerably 
  complicated 
  by 
  the 
  

   ionizations 
  which 
  take 
  place 
  with 
  them. 
  The 
  result 
  o£ 
  Ktihne 
  

   that 
  pepsinpeptone 
  diffuses 
  only 
  half 
  as 
  slowly 
  as 
  glucose 
  

   (twice 
  as 
  fast) 
  seems 
  incompatible 
  with 
  the 
  results 
  of 
  the 
  

   present 
  paper 
  (see 
  Cohnheim's 
  Chemie 
  der 
  Eiweisskdrper, 
  

   p. 
  87). 
  The 
  diffusion 
  of 
  the 
  peptones 
  is 
  worth 
  thorough 
  

   investigation 
  for 
  its 
  bearings 
  upon 
  the 
  whole 
  physical 
  

   chemistry 
  of 
  digestion. 
  

  

  By 
  this 
  method 
  we 
  shall 
  now 
  investigate 
  the 
  Na 
  salts 
  of 
  

   globulin 
  and 
  casein. 
  For 
  Hardy's 
  data 
  for 
  the 
  conductivity 
  

   of 
  solutions 
  of 
  Na 
  globulin 
  I 
  have 
  found 
  the 
  following 
  formula 
  

   to 
  hold 
  with 
  the 
  units 
  used 
  in 
  this 
  paper 
  (Proc. 
  Roy. 
  Soc. 
  B. 
  

   lxxix. 
  p. 
  146) 
  : 
  — 
  

  

  \=22 
  + 
  1/(0-005 
  + 
  3*1 
  mi). 
  . 
  . 
  . 
  (13) 
  

  

  At 
  infinite 
  dilution 
  this 
  gives 
  \ 
  = 
  222, 
  which 
  is 
  a 
  little 
  

   greater 
  than 
  the 
  218'4 
  of 
  Kohlrausch 
  for 
  NaOH 
  at 
  18° 
  and 
  

   infinite 
  dilution. 
  The 
  remarkable 
  point 
  about 
  this 
  formula 
  

   is 
  the 
  functioning 
  of 
  one 
  half 
  of 
  the 
  Na 
  in 
  quite 
  a 
  different 
  

   capacity 
  from 
  the 
  other, 
  shown 
  by 
  the 
  term 
  22 
  = 
  44/2 
  which 
  

   is 
  independent 
  of 
  the 
  concentration. 
  Moreover, 
  although 
  at 
  

   infinite 
  dilution 
  the 
  conductivity 
  is 
  nearly 
  that 
  of 
  NaOH, 
  at 
  

   ordinary 
  finite 
  dilutions 
  it 
  is 
  much 
  smaller 
  than 
  that 
  of 
  NaOH 
  

   because 
  the 
  coefficient 
  3*1 
  is 
  so 
  large. 
  This 
  large 
  coefficient 
  

   is 
  due 
  to 
  the 
  globulin 
  whose 
  ions 
  involve 
  the 
  half 
  of 
  the 
  Na 
  

   ions 
  and 
  all 
  the 
  OH 
  ions 
  in 
  a 
  greater 
  viscosity 
  of 
  electric 
  

   origin. 
  The 
  globulin 
  ions 
  act 
  as 
  an 
  electric 
  brake 
  upon 
  the 
  

   electrically 
  driven 
  OH 
  ions 
  and 
  half 
  of 
  the 
  Na 
  ions. 
  Thus 
  

   although 
  the 
  experiments 
  with 
  Na 
  globulin 
  are 
  not 
  yet 
  

   refined 
  enough 
  in 
  practice 
  and 
  theory 
  to 
  yield 
  directly 
  the 
  

   conductivity 
  of 
  the 
  globulin 
  ion, 
  they 
  give 
  us 
  the 
  viscosity 
  

   of 
  electric 
  origin 
  due 
  to 
  the 
  globulin 
  ion, 
  and 
  thus 
  enable 
  us 
  

   to 
  find 
  its 
  conductivity 
  and 
  volume 
  by 
  the 
  methods 
  of 
  the 
  

   present 
  paper, 
  if 
  we 
  accept 
  Hardy's 
  conclusion 
  that 
  v 
  2 
  is 
  

   probably 
  2. 
  Let 
  us 
  write 
  (13) 
  in 
  the 
  general 
  form 
  

  

  X 
  = 
  A 
  ofl 
  /2 
  + 
  l/{l/(A 
  o6 
  /2 
  + 
  A 
  oa 
  )+6m*}, 
  . 
  . 
  (14) 
  

  

  where 
  A 
  & 
  represents 
  the 
  conductivity 
  of 
  the 
  positive 
  ion 
  

   like 
  Na, 
  and 
  A 
  „ 
  represents 
  that 
  of 
  OH. 
  Probably 
  A 
  02 
  the 
  

   conductivity 
  of 
  the 
  globulin 
  or 
  similar 
  ion 
  ought 
  to 
  appear 
  

   on 
  the 
  right 
  side 
  as 
  an 
  additional 
  term, 
  but 
  it 
  is 
  best 
  

   omitted 
  till 
  it 
  emerges 
  clearly 
  from 
  the 
  experiments. 
  For 
  

   NH 
  4 
  globulin 
  this 
  formula 
  holds 
  just 
  as 
  ior 
  Na 
  globulin. 
  

   I 
  shall 
  now 
  show 
  that 
  it 
  applies 
  to 
  Na 
  and 
  NH 
  4 
  casein, 
  

   thereby 
  strengthening 
  considerably 
  the 
  validity 
  of 
  its 
  form 
  

  

  