﻿The 
  Relation 
  of 
  Spermatozoa 
  to 
  Certain 
  Electrolytes. 
  153 
  

  

  charged 
  trivalent 
  ions 
  cause 
  no 
  precipitation 
  ; 
  in 
  alkaline 
  solutions 
  the 
  

   particles 
  are 
  negatively 
  charged, 
  and 
  positive 
  trivalent 
  ions 
  cause 
  precipita- 
  

   tion 
  by 
  reducing 
  the 
  charge 
  to 
  the 
  isoelectric 
  value. 
  

  

  Finally, 
  it 
  must 
  be 
  mentioned 
  that 
  spermatozoa 
  which 
  have 
  been 
  aggluti- 
  

   nated 
  by 
  cerium 
  or 
  lanthanum 
  are 
  dispersed 
  by 
  acid 
  sea 
  water, 
  and 
  the 
  

   concentration 
  of 
  acid 
  required 
  coincides 
  with 
  the 
  critical 
  values 
  found 
  in 
  

   such 
  experiments 
  mentioned 
  in 
  Table 
  VII. 
  The 
  addition 
  of 
  further 
  cerium 
  

   to 
  such 
  acid 
  suspensions 
  causes 
  no 
  agglutination. 
  

  

  This 
  fact 
  is 
  important, 
  as 
  it 
  shows 
  very 
  clearly 
  that 
  the 
  effect 
  of 
  cerium 
  

   on 
  a 
  normal 
  sperm 
  suspension 
  is 
  of 
  the 
  same 
  nature, 
  but 
  much 
  less 
  intense 
  

   than 
  that 
  of 
  acids. 
  Acids 
  never 
  agglutinate 
  spermatozoa, 
  but 
  at 
  a 
  critical 
  

   concentration 
  the 
  surface 
  charge 
  changes 
  with 
  great 
  rapidity 
  from 
  negative 
  

   to 
  positive, 
  and 
  in 
  each 
  case 
  maximum 
  dispersal 
  exists 
  just 
  as 
  in 
  a 
  weak 
  

   globulin 
  solution, 
  which 
  contains 
  a 
  high 
  concentration 
  of 
  neutral 
  salts. 
  

   Cerium 
  or 
  lanthanum, 
  however, 
  have 
  a 
  much 
  less 
  intense 
  action 
  than 
  the 
  

   hydrogen 
  ion 
  ; 
  the 
  trivalent 
  ions 
  reduce 
  the 
  normal 
  negative 
  charge, 
  but 
  they 
  

   cannot 
  convey 
  a 
  sufficient 
  positive 
  charge 
  to 
  cause 
  dispersion 
  ; 
  hence, 
  sperma- 
  

   tozoa 
  agglutinated 
  by 
  cerium 
  can 
  be 
  dispersed 
  either 
  by 
  acids 
  or 
  by 
  trivalent 
  

   negative 
  ions 
  ; 
  in 
  the 
  former 
  case 
  dispersion 
  being 
  due 
  to 
  a 
  positive 
  charge 
  

   and 
  in 
  the 
  latter 
  to 
  a 
  negative 
  charge. 
  

  

  The 
  intense 
  action 
  of 
  the 
  hydrogen 
  ion 
  is 
  paralleled 
  by 
  the 
  experiments 
  of 
  

   Perrin 
  and 
  Mines, 
  and 
  also 
  by 
  the 
  interesting 
  work 
  of 
  Ellis 
  (4). 
  The 
  latter 
  

   author 
  has 
  shown 
  that 
  the 
  maximum 
  surface 
  potential 
  on 
  an 
  oil-water 
  

   interface 
  exists 
  in 
  the 
  region 
  of 
  " 
  neutrality 
  " 
  — 
  the 
  addition 
  of 
  acid 
  very 
  

   rapidly 
  reduces 
  this 
  potential, 
  while 
  alkalis 
  reduce 
  it 
  somewhat 
  more 
  slowly. 
  

   This 
  latter 
  point 
  is 
  of 
  interest, 
  when 
  we 
  consider 
  the 
  effects 
  of 
  alkalis 
  upon 
  

   sperm 
  suspensions. 
  As 
  stated 
  in 
  a 
  previous 
  paper 
  (8), 
  the 
  effect 
  of 
  fairly 
  

   strong 
  alkaline 
  sea 
  water 
  is 
  to 
  agglutinate 
  the 
  spermatozoa. 
  The 
  action 
  is, 
  

   however, 
  less 
  complete 
  than 
  that 
  of 
  cerium, 
  and 
  it 
  will 
  be 
  noted 
  that 
  some 
  

   doubt 
  may 
  exist 
  as 
  to 
  whether 
  the 
  two 
  phenomena 
  are 
  comparable. 
  In 
  the 
  

   first 
  place, 
  the 
  agglutination 
  of 
  sperm 
  by 
  alkali 
  shows 
  well 
  marked 
  grades 
  of 
  

   agglutination 
  with 
  increasing 
  P 
  H 
  — 
  , 
  also 
  a 
  concentration 
  of 
  alkali 
  which 
  is 
  

   sufficient 
  to 
  strongly 
  agglutinate 
  the 
  vast 
  majority 
  of 
  the 
  spermatozoa 
  allows 
  

   the 
  minority 
  to 
  continue 
  in 
  active 
  movement 
  for 
  a 
  considerable 
  time. 
  Again, 
  

   with 
  alkali 
  of 
  varying 
  strength, 
  a 
  complete 
  series 
  of 
  intermediate 
  conditions 
  

   of 
  agglutination 
  is 
  obtained 
  from 
  complete 
  agglutination 
  to 
  complete 
  dispersal, 
  

   a 
  phenomenon 
  which 
  is 
  not 
  observed 
  in 
  the 
  case 
  of 
  cerium. 
  Finally, 
  con- 
  

   centrations 
  of 
  alkali 
  which 
  cause 
  marked 
  agglutination 
  injure 
  the 
  cells, 
  which 
  

   then 
  stain 
  yellow 
  instead 
  of 
  red 
  with 
  neutral 
  red, 
  showing 
  that 
  the 
  interior 
  

   of 
  the 
  cell 
  has 
  been 
  affected 
  by 
  the 
  alkali. 
  

  

  