In  a  further  stage  (Fig.  4),  one  of  the  halves  of  the  nucleus  had 
nioved  close  to  the  blepharoplast  (extranuclear  centrosome),  whereas 
the  second  half  seemed  to  lose  its  staining  properties,  taking  the 
haematoxylin  stain  in  a  somewhat  diffuse  manner.  The  parasites 
were  markedly  increased  in  size.  At  this  stage  the  cytoplasm  appeared 
to  become  denser  in  that  end  of  the  parasite  in  which  the  blepharoplast 
was  situated  (Fig.  5),  whereas  the  cytuplasm  of  the  opposite  end 
exhibited  a  somewhat  ragged  appearance,  and  seemed  to  have  lost 
its  well-defined  outline.  At  a  still  later  stage,  the  meshes  of  the 
‘  Schaumplasma'  became  larger  and  larger  and  less  defined,  and  the 
cytoplasm  about  the  flagellum  more  and  more  disintegrated  (Fig.  6), 
until,  finally,  only  the  blepharoplast  end  was  left  with  a  long  wavy 
flagellum.  The  half  of  the  nucleus  in  the  flagellar  end  lost  its  staining 
properties  to  a  gradually  increasing  extent,  and  sometimes  the  cyto¬ 
plasm  contained  a  round,  sharply-defined,  darkly-staining  vacuole, 
which  was  probably  the  remains  of  the  degenerated  half  of  the  nucleus. 
The  other  half  of  the  nucleus  underwent  further  changes  ;  it  increased 
in  size  and  changed  its  position  with  regard  to  the  blepharoplast,  in 
many  instances  appearing  behind  the  blepharoplast.  As  a  rule,  it 
contained  only  one  intranuclear  centrosome,  occasionally,  howeA'er, 
two  (Fig.  7). 
Judging  from  the  number  of  trypanosomes  in  the  different  stages 
of  development,  it  is  probable  that  after  the  division  of  the  intra¬ 
nuclear  centrosome  (karyosome),  the  complete  division  of  the  nucleus 
takes  place  in  a  comparatively  short  time.  Forms  like  Figs.  1-3  and 
Figs.  6-8  were  often  seen,  whereas  those  shown  in  Figs.  4-5  were 
comparatively  rare. 
Slight  modifications  of  this  process  were  sometimes  noticed,  At 
times  the  parasite  did  not  grow  to  the  large  size  seen  in  Figs.  4-6, 
whilst  at  other  times  the  divided  nuclei  remained  connected  by  a  thin 
strand  for  a  considerable  time  (Fig.  10). 
Uuring  these  changes  in  the  nucleus  and  cytoplasm  of  the  parasite, 
the  blepharoplast  did  not  undergo  any  marked  transformation  bej'ond 
slight  enlargement.  In  some  cases,  as  in  Figs.  5-8,  it  seemed  to 
consist  of  a  number  of  round  granules,  but  not  even  in  the  best 
differentiated  specimens  could  any  detailed  structure  be  made  out. 
.■\1  a  later  stage,  parasites  were  seen  resembling  spermatozoa, 
consisting  of  an  oval  head  with  a  long  flagellum,  as  well  as  a  few 
