﻿THE 
  DKVKLOPMENT 
  OF 
  FLAGELLATiilD 
  ORGANISMS. 
  373 
  

  

  Stages 
  of 
  Development 
  after 
  Seventy-two 
  Hours. 
  

   — 
  The 
  third 
  day 
  is 
  characterised 
  by 
  tlie 
  elongation 
  of 
  the 
  

   conjugating 
  pairs 
  of 
  organisms, 
  and 
  the 
  first 
  appearance 
  of 
  

   flagellated 
  forms, 
  although 
  sometimes 
  the 
  latter 
  may 
  not 
  be 
  

   found 
  until 
  the 
  fourth 
  day. 
  The 
  commonest 
  appearance 
  of 
  

   these 
  pyriform 
  bodies 
  is 
  that 
  shown 
  in 
  fig. 
  1 
  of 
  line 
  V, 
  in 
  

   which 
  the 
  macron 
  uclei 
  are 
  seen 
  in 
  the 
  thick 
  ends 
  of 
  the 
  

   organisms, 
  while 
  the 
  micronuclei 
  have 
  passed 
  to 
  the 
  thinner 
  

   ends 
  from 
  which 
  the 
  flagella 
  will 
  eventually 
  arise. 
  In 
  Case 
  

   58, 
  from 
  which 
  the 
  figures 
  of 
  lines 
  II 
  to 
  V 
  have 
  been 
  drawn, 
  

   the 
  culture-tube 
  was 
  unfortunately 
  left 
  out 
  of 
  the 
  cold 
  incu- 
  

   bator 
  for 
  half 
  an 
  hour 
  owing 
  to 
  an 
  interruption 
  in 
  ray 
  work, 
  

   and 
  no 
  further 
  development 
  occurred 
  although 
  the 
  tempera- 
  

   ture 
  of 
  the 
  laboratory 
  was 
  only 
  28° 
  C. 
  at 
  the 
  time 
  ; 
  so 
  sensitive 
  

   are 
  the 
  partially-developed 
  forms 
  to 
  a 
  rise 
  of 
  the 
  thermometer. 
  

   In 
  Case 
  47 
  some 
  early 
  flagellated 
  forms 
  were 
  found 
  on 
  the 
  

   third 
  day, 
  as 
  shown 
  in 
  figs. 
  4, 
  5, 
  and 
  6 
  of 
  line 
  IX. 
  In 
  these 
  

   only 
  a 
  single 
  flagellum 
  has 
  yet 
  developed 
  although 
  two 
  of 
  the 
  

   forms 
  are 
  distinctly 
  double 
  ones, 
  while 
  some 
  which 
  appear 
  to 
  

   be 
  single 
  are 
  really 
  double 
  ones 
  lying 
  on 
  one 
  side, 
  for 
  inter- 
  

   mediate 
  appearances 
  showing 
  the 
  double 
  nuclei 
  partially 
  

   obscuring 
  each 
  other 
  in 
  this 
  manner 
  have 
  been 
  met 
  with. 
  

   The 
  remaining 
  forms 
  shown 
  in 
  line 
  IX 
  have 
  all 
  reached 
  the 
  

   elongated 
  stage 
  although 
  still 
  without 
  flagella. 
  

  

  Stage 
  of 
  Development 
  after 
  Ninety-six 
  Hours. 
  — 
  

   In 
  the 
  figures 
  of 
  line 
  X 
  are 
  shown 
  some 
  of 
  the 
  flagellated 
  

   forms 
  found 
  on 
  the 
  fourth 
  day 
  in 
  Case 
  47, 
  in 
  addition 
  to 
  which 
  

   there 
  were 
  much 
  more 
  numerous 
  double 
  pyriform 
  organisms 
  

   without 
  flagella, 
  for 
  only 
  a 
  very 
  small 
  percentage 
  of 
  the 
  con- 
  

   jugating 
  forms 
  eventually 
  reach 
  the 
  flagellated 
  stage 
  under 
  

   the 
  artificial 
  conditions 
  of 
  the 
  cultures, 
  which 
  must 
  be 
  very 
  

   far 
  from 
  being 
  as 
  favourable 
  to 
  the 
  development 
  of 
  the 
  

   organism 
  as 
  the 
  natural 
  conditions 
  in 
  which 
  it 
  takes 
  place, 
  

   whatever 
  they 
  may 
  be. 
  Nevertheless, 
  the 
  elongated 
  flagel- 
  

   lated 
  forms 
  have 
  now 
  been 
  found 
  in 
  eight 
  different 
  cases, 
  

   including 
  two 
  of 
  kala-azar 
  from 
  Assam. 
  In 
  fig. 
  3 
  of 
  line 
  X 
  

   the 
  two 
  flagellated 
  bodies 
  have 
  apparently 
  just 
  separated. 
  

  

  