﻿154 
  

  

  Mr. 
  J. 
  Gray. 
  

  

  It 
  is 
  therefore 
  possible 
  that 
  agglutination 
  of 
  spermatozoa 
  by 
  alkali 
  is 
  a 
  

   distinct 
  phenomena 
  from 
  that 
  of 
  agglutination 
  by 
  cerium 
  ; 
  at 
  the 
  same 
  time 
  

   it 
  is 
  interesting 
  to 
  note 
  that 
  Ellis 
  found 
  that 
  alkali 
  reduces 
  the 
  potential 
  

   between 
  an 
  oil-water 
  interface, 
  although 
  its 
  aotion 
  is 
  less 
  intense 
  than 
  that 
  of 
  

   acids, 
  so 
  that 
  it 
  is 
  possible 
  that 
  the 
  agglutination 
  of 
  spermatozoa 
  by 
  alkali 
  is 
  

   due 
  to 
  a 
  reduction 
  in 
  the 
  negative 
  surface 
  charge. 
  It 
  should, 
  however, 
  be 
  

   mentioned 
  that 
  no 
  evidence 
  was 
  obtained 
  to 
  show 
  that 
  the 
  agglutinative 
  

   power 
  of 
  cerium 
  was 
  increased 
  by 
  raising 
  the 
  P 
  H 
  of 
  sea 
  water 
  above 
  the 
  

   normal. 
  

  

  08 
  _ 
  

  

  ■10 
  os 
  o 
  OS 
  10 
  

  

  NaOH 
  HCl 
  

  

  Diagram 
  (after 
  Ellis) 
  showing 
  Kelation 
  of 
  Contact 
  Potential 
  of 
  an 
  Oil-Water 
  Interface 
  

   and 
  Hydrogen 
  Ion 
  Concentration 
  of 
  Water 
  phase. 
  

  

  Summary 
  of 
  Experimental 
  Results. 
  

  

  A 
  suspension 
  of 
  the 
  spermatozoa 
  of 
  Echinus 
  miliaris 
  in 
  sea 
  water 
  behaves 
  

   towards 
  trivalent 
  positive 
  ions 
  in 
  exactly 
  the 
  same 
  way 
  as 
  a 
  suspension 
  of 
  

   negatively 
  charged 
  particles 
  of 
  such 
  colloids 
  as 
  albumen 
  or 
  globulin. 
  It 
  is 
  

   only 
  in 
  those 
  solutions 
  which 
  are 
  capable 
  of 
  maintaining 
  the 
  normal 
  negative 
  

   charge 
  that 
  movement 
  of 
  spermatozoa 
  can 
  take 
  place. 
  Trivalent 
  ions 
  

   flocculate 
  sperm 
  suspensions 
  by 
  removing 
  the 
  negative 
  charge. 
  The 
  action 
  of 
  

   the 
  hydrogen 
  ion 
  is 
  very 
  intense 
  and 
  changes 
  the 
  surface 
  charge 
  from 
  negative 
  

   to 
  positive 
  without 
  any 
  intermediate 
  flocculation. 
  

  

  