﻿their 
  Sodium 
  Salts 
  on 
  Zupinus 
  Albus. 
  191 
  

  

  limit. 
  This 
  unusual 
  viciousness 
  is 
  plainly 
  to 
  be 
  charged 
  in 
  

   large 
  part 
  to 
  the 
  undissociated 
  molecules, 
  but 
  the 
  anions 
  here 
  

   seem 
  to 
  be 
  much 
  more 
  significant 
  than 
  in 
  any 
  acid 
  before 
  men- 
  

   tioned. 
  Probably 
  about 
  785 
  units 
  are 
  chargeable 
  to 
  the 
  anions, 
  

  

  + 
  + 
  

  

  about 
  15 
  units 
  to 
  Na 
  ions, 
  about 
  2880 
  units 
  toH 
  ions 
  and 
  about 
  

  

  9135 
  units 
  to 
  the 
  residual 
  molecules. 
  

  

  For 
  comparison 
  with 
  the 
  above 
  organic 
  acids, 
  in 
  which 
  the 
  

   acid 
  H 
  is 
  in 
  the 
  carboxyl 
  form 
  (COOH), 
  carbolic 
  acid 
  and 
  its 
  

   Na 
  compound 
  have 
  been 
  added. 
  Here 
  the 
  H 
  is 
  in 
  the 
  

   hydroxyl 
  form 
  (OH). 
  The 
  toxic-value 
  of 
  carbolic 
  acid 
  is 
  400 
  

   (8), 
  about 
  -jV 
  tn 
  tnat 
  °f 
  ^he 
  completely 
  ionized 
  mono-basic 
  acid. 
  

   A 
  study 
  of 
  the 
  electrical 
  conductivity 
  has 
  shown 
  (9) 
  that 
  ioni- 
  

   zation 
  is 
  practically 
  absent 
  here, 
  and 
  the 
  undissociated 
  mole- 
  

   cules 
  form, 
  of 
  course, 
  the 
  only 
  factor. 
  No 
  diminution 
  of 
  the 
  

   toxic-value 
  would 
  be 
  expected, 
  therefore, 
  in 
  the 
  Na 
  compound. 
  

   As 
  a 
  matter 
  of 
  fact 
  (8), 
  the 
  toxic 
  limit 
  of 
  the 
  Na 
  compound 
  is 
  

   likewise 
  400. 
  This 
  is 
  a 
  situation 
  fairly 
  typical 
  for 
  the 
  phenols. 
  

  

  Summary. 
  — 
  In 
  closing, 
  the 
  main 
  points 
  brought 
  out 
  in 
  the 
  

   course 
  of 
  the 
  above 
  discussion 
  may 
  be 
  summarized 
  as 
  follows 
  : 
  

  

  Given 
  the 
  degree 
  of 
  ionization 
  of 
  the 
  molecules 
  of 
  an 
  acid 
  

   and 
  of 
  its 
  Na 
  salt 
  at 
  the 
  limit-concentrations, 
  it 
  is 
  possible 
  

   approximately 
  to 
  analyze 
  the 
  resultant 
  toxic 
  effect 
  into 
  those 
  

  

  component 
  parts 
  which 
  are 
  due 
  (1) 
  to 
  the 
  H 
  ions, 
  (2) 
  to 
  the 
  

   anions 
  and, 
  in 
  case 
  ionization 
  is 
  incomplete, 
  (3) 
  to 
  the 
  residual 
  

   undissociated 
  molecules. 
  

  

  In 
  the 
  inorganic 
  acids 
  cited, 
  complete 
  ionization 
  exists 
  at 
  the 
  

   limit-concentration, 
  e.g., 
  in 
  HC1, 
  HBr, 
  HN0 
  3 
  and 
  others. 
  The 
  

   anions 
  are 
  probably 
  toxic, 
  but 
  in 
  a 
  very 
  slight 
  degree 
  when 
  

  

  compared 
  with 
  H. 
  Consequently, 
  in 
  these 
  acids 
  the 
  purest 
  H 
  

   effect 
  is 
  seen 
  and 
  the 
  minimum 
  effect 
  from 
  other 
  constituents. 
  

  

  - 
  

   Na 
  ions 
  are 
  but 
  slightly 
  toxic. 
  

  

  In 
  both 
  the 
  fatty 
  and 
  the 
  aromatic 
  series 
  of 
  organic 
  acids, 
  the 
  

   acids 
  dissociate 
  much 
  less 
  freely 
  as 
  a 
  rule 
  and 
  exert 
  their 
  toxic 
  

  

  + 
  

   action 
  usually 
  through 
  three 
  factors 
  : 
  H 
  ions, 
  anions 
  and 
  

   residual 
  undissociated 
  molecules. 
  In 
  case 
  dissociation 
  is 
  well 
  

  

  nigh 
  complete, 
  the 
  partial-toxicity 
  of 
  H 
  ions 
  usually 
  exceeds 
  

   that 
  of 
  other 
  factors. 
  In 
  case 
  ionization 
  takes 
  place 
  less 
  freely, 
  

   the 
  undissociated 
  molecule 
  plays 
  an 
  important 
  part, 
  often 
  

  

  exceeding 
  that 
  played 
  by 
  H 
  ions. 
  In 
  general, 
  such 
  residual 
  

   molecules 
  possess 
  a 
  great 
  degree 
  of 
  toxicity. 
  In 
  cinnamic 
  acid 
  

   over 
  77 
  per 
  cent 
  of 
  the 
  total 
  toxic 
  action 
  is 
  due 
  to 
  undissociated 
  

   molecules. 
  

  

  