﻿their 
  Sodium 
  Salts 
  on 
  Zujpinus 
  Albus. 
  189 
  

  

  limits. 
  This 
  fact, 
  while 
  not 
  giving 
  a 
  numerically 
  accurate 
  

   ground 
  for 
  argument, 
  permits 
  us, 
  nevertheless, 
  to 
  arrive 
  at 
  a 
  

   rough 
  idea 
  of 
  the 
  relative 
  effectiveness 
  of 
  ions 
  and 
  undisso- 
  

   ciated 
  molecules. 
  To 
  illustrate, 
  formic 
  acid 
  owes 
  to 
  the 
  action 
  

   of 
  the 
  anions 
  of 
  70 
  per 
  cent 
  of 
  its 
  molecules 
  plus 
  30 
  per 
  cent 
  of 
  

   un-ionized 
  molecules 
  remaining, 
  30 
  per 
  cent 
  of 
  its 
  toxic- 
  value, 
  

   1920 
  units. 
  Sodium 
  formate 
  has 
  a 
  toxic-value 
  of 
  about 
  50. 
  It 
  

   has 
  been 
  shown 
  above 
  that 
  the 
  partial-toxicity 
  characteristic 
  for 
  

  

  100 
  per 
  cent 
  of 
  Na 
  ions 
  is 
  less 
  than 
  16; 
  here, 
  therefore, 
  the 
  

  

  partial-toxicity 
  due 
  to 
  Na 
  ions 
  cannot 
  be 
  more 
  than 
  14- 
  and 
  is 
  

   doubtless 
  less. 
  This 
  leaves 
  about 
  36 
  units 
  due 
  to 
  anions 
  derived 
  

   from 
  the 
  ionization 
  of 
  90 
  per 
  cent 
  of 
  the 
  molecules 
  plus 
  that 
  due 
  

   to 
  the 
  residual 
  10 
  per 
  cent 
  of 
  molecules 
  not 
  thus 
  ionized. 
  

   Plainly 
  the 
  toxic- 
  value 
  of 
  either 
  of 
  these 
  factors 
  cannot 
  exceed 
  

   the 
  sum 
  36. 
  One 
  may 
  roughly 
  say 
  that 
  the 
  toxic-value 
  of 
  these 
  

   anions 
  derived 
  from 
  90 
  per 
  cent 
  of 
  the 
  molecules 
  is 
  less 
  than 
  

   36. 
  Since 
  in 
  the 
  acid 
  70 
  per 
  cent 
  of 
  the 
  same 
  anions 
  are 
  

   formed, 
  in 
  a 
  more 
  dilute 
  solution 
  the 
  action 
  of 
  the 
  anions 
  must 
  

   be 
  still 
  less. 
  One 
  may, 
  however, 
  safely 
  express 
  it 
  still 
  as 
  less 
  

   than 
  36. 
  Comparing 
  this 
  value 
  with 
  the 
  sum 
  of 
  the 
  values 
  of 
  

   anions 
  plus 
  undissociated 
  molecules, 
  the 
  action 
  of 
  the 
  anions 
  is 
  

   seen 
  to 
  sink 
  into 
  insignificance, 
  and 
  the 
  toxic-value 
  due 
  to 
  the 
  

   sum 
  is 
  practically 
  due 
  to 
  30 
  per 
  cent 
  of 
  undissociated 
  molecules. 
  

  

  In 
  acetic 
  acid, 
  but 
  15 
  per 
  cent 
  of 
  the 
  molecules 
  are 
  ionized 
  at 
  

   a 
  concentration 
  of 
  one 
  gram-molecule 
  in 
  1600 
  liters 
  ; 
  neverthe- 
  

   less, 
  60 
  per 
  cent 
  of 
  the 
  toxicity 
  of 
  the 
  acid 
  is 
  due 
  to 
  II 
  ions 
  

   derived 
  from 
  this 
  proportion 
  of 
  molecules 
  ; 
  85 
  per 
  cent 
  of 
  

   undissociated 
  molecules 
  plus 
  15 
  per 
  cent 
  of 
  anions 
  are 
  responsible 
  

   for 
  610 
  units 
  or 
  40 
  per 
  cent 
  of 
  the 
  toxicity 
  of 
  the 
  acid. 
  A 
  

   calculation 
  similar 
  to 
  the 
  above 
  based 
  on 
  the 
  action 
  of 
  the 
  

   sodium 
  salt 
  shows 
  that 
  in 
  this 
  acid, 
  again, 
  the 
  anions 
  can 
  play 
  

   no 
  measurable 
  part, 
  the 
  undissociated 
  molecules, 
  of 
  which 
  85 
  

   per 
  cent 
  are 
  present, 
  being 
  responsible 
  for 
  practically 
  40 
  per 
  

   cent 
  of 
  the 
  toxic 
  action 
  of 
  the 
  acid. 
  

  

  In 
  the 
  remaining 
  members 
  of 
  the 
  fatty 
  series 
  studied, 
  the 
  

   relative 
  importance 
  of 
  the 
  action 
  of 
  the 
  residual 
  molecules 
  

   increases 
  ; 
  in 
  both 
  propionic 
  and 
  butyric 
  acids 
  the 
  undisso- 
  

   ciated 
  molecules 
  comprise 
  about 
  80 
  per 
  cent 
  of 
  the 
  total 
  num- 
  

   ber, 
  and 
  exert 
  about 
  65 
  per 
  cent 
  of 
  the 
  toxic 
  action 
  of 
  these 
  

   acids. 
  

  

  Aromatic 
  Series. 
  — 
  The 
  study 
  of 
  the 
  aromatic 
  compounds 
  

   has 
  been 
  very 
  seriously 
  limited 
  by 
  lack 
  of 
  data 
  from 
  the 
  

   physico-chemical 
  side. 
  This 
  is 
  especially 
  true 
  of 
  the 
  sodium 
  

   compounds, 
  a 
  large 
  number 
  of 
  which 
  seem 
  not 
  to 
  have 
  received 
  

   study 
  along 
  the 
  line 
  of 
  their 
  electrolytic 
  dissociation, 
  in 
  but 
  

  

  