﻿536 
  Mr. 
  G. 
  H. 
  Livens 
  on 
  the 
  Intrinsic 
  

  

  solutions- 
  — 
  such, 
  for 
  instance, 
  as 
  dissociation, 
  breaking 
  down 
  

   or 
  formation 
  of 
  molecular 
  aggregates, 
  hydrolysis, 
  and 
  other 
  

   not 
  precisely 
  known 
  actions 
  — 
  may 
  cause 
  a 
  variation 
  in 
  the 
  

   optical 
  rotative 
  power 
  of 
  the 
  solution; 
  and, 
  in 
  fact, 
  each 
  of 
  

   these 
  actions 
  has 
  in 
  turn 
  been 
  suggested 
  as 
  the 
  cause 
  of 
  the 
  

   variation. 
  It 
  is 
  our 
  present 
  object 
  to 
  discuss 
  the 
  more 
  im- 
  

   portant 
  suggestions 
  on 
  these 
  lines 
  to 
  see 
  how 
  they 
  may 
  be 
  

   regarded 
  as 
  accounting 
  for 
  the 
  facts. 
  Although 
  such 
  a 
  dis- 
  

   cussion 
  leads 
  to 
  a 
  probable 
  rejection 
  of 
  all 
  of 
  these 
  actions, 
  as 
  

   having 
  no 
  effect 
  on 
  the 
  rotative 
  power 
  of 
  the 
  solution, 
  certain 
  

   important 
  deductions 
  can 
  be 
  drawn 
  from 
  the 
  evidence 
  ad- 
  

   vanced 
  in 
  support 
  of 
  the 
  various 
  h} 
  T 
  potheses, 
  which 
  indicate, 
  

   moreover, 
  the 
  lines 
  along 
  which 
  future 
  investigation 
  must 
  go. 
  

   We 
  consider 
  these 
  suggestions 
  in 
  turn. 
  

  

  1. 
  Electrolytic 
  Dissociation. 
  — 
  The 
  evidence 
  advanced 
  in 
  

   support 
  of 
  an 
  effect 
  of 
  this 
  kind 
  is 
  well 
  and 
  impartially 
  

   analysed 
  by 
  Landolt 
  in 
  his 
  book, 
  and 
  I 
  shall 
  here 
  only 
  give 
  a 
  

   summary 
  of 
  the 
  arguments. 
  

  

  The 
  origin 
  of 
  the 
  explanation 
  by 
  electrolytic 
  dissociation 
  

   was 
  the 
  discovery 
  that 
  the 
  molecular 
  rotations 
  of 
  a 
  number 
  

   of 
  neutral 
  salts 
  of 
  tartaric 
  acid 
  in 
  solution 
  in 
  water 
  all 
  

   approximated 
  to 
  the 
  same 
  value 
  as 
  the 
  solutions 
  were 
  more 
  

   and 
  more 
  diluted. 
  By 
  making 
  similar 
  experiments 
  with 
  

   solutions 
  of 
  certain 
  active 
  alkaloids 
  neutralized 
  in 
  different 
  

   acids, 
  Oudemanns 
  found 
  that 
  the 
  rotation 
  of 
  the 
  alkaloids 
  

   in 
  dilute 
  solutions 
  in 
  water 
  did 
  not 
  depend 
  on 
  the 
  acids, 
  

   and 
  from 
  his 
  result 
  he 
  deduced 
  his 
  well-known 
  rule 
  ex- 
  

   pressing 
  this 
  fact. 
  The 
  rule 
  was 
  later 
  extended 
  to 
  active 
  

   acids 
  on 
  the 
  grounds 
  that 
  certain 
  acids 
  after 
  saturation 
  with 
  

   different 
  bases, 
  or 
  in 
  the 
  form 
  of 
  dilute 
  solutions 
  of 
  their 
  salts, 
  

   always 
  have 
  practically 
  the 
  same 
  rotativity. 
  Further 
  expe- 
  

   riments 
  on 
  the 
  influence 
  of 
  the 
  concentration 
  on 
  the 
  rotation 
  

   of 
  solutions 
  of 
  salts 
  of 
  malic 
  and 
  other 
  acids 
  have 
  shown 
  that 
  

   their 
  molecular 
  rotations, 
  which 
  are 
  very 
  different 
  in 
  concen- 
  

   trated 
  solutions, 
  agree 
  more 
  and 
  more 
  as 
  the 
  dilution 
  is 
  

   increased. 
  

  

  An 
  explanation 
  of 
  these 
  phenomena 
  was 
  first 
  attempted 
  by 
  

   Hadrich 
  on 
  the 
  basis 
  of 
  Arrhenius' 
  theory 
  of 
  electrolytic 
  

   dissociation. 
  His 
  idea 
  was 
  essentially 
  that 
  in 
  the 
  dilute 
  

   solution 
  the 
  active 
  ion, 
  being 
  completely 
  dissociated 
  from 
  the 
  

   inactive 
  ion, 
  w 
  r 
  ould 
  exert 
  its 
  influence 
  unhampered 
  by 
  that 
  ion. 
  

   Apparent 
  confirmation 
  of 
  the 
  theory 
  was 
  provided 
  by 
  experi- 
  

   ments 
  conducted 
  by 
  Hadrich 
  himself, 
  who 
  examined 
  solutions 
  

   of 
  various 
  active 
  alkaloids 
  neutralized 
  with 
  different 
  acids. 
  

   His 
  results, 
  in 
  general 
  agreement 
  with 
  those 
  mentioned 
  

   above, 
  show 
  that 
  (i.) 
  the 
  molecular 
  rotation 
  of 
  each 
  salt 
  

  

  