one  or  two  small  folds.  The  flagellar  rim  stains  deeply ;  arising 
from  an  achromatic  area,  it  is  continued  as  a  free  portion  of  up  to 
8-5  yu  in  length. 
B.  ‘Short  forms!  In  fresh  preparations  this  trypanosome  is 
slightly  more  active  than  the  tadpole  of  T.  dimorphon ;  the 
difference,  however,  is  only  appreciable  on  close  comparison. 
Stained,  it  is  indistinguishable  from  the  tadpole  forms  of 
7',  dimorphon.  In  length  it  measures  from  1075  to  I4'8  yu  (average 
13-56  fi),  and  is  from  1-25  to  1-65  yu  in  width.  The  mean  of  a  series 
of  measurements  gives  .-  — 
Extremity  to  Nucleus  to  flagellar 
Nucleus  Nucleus  extremity 
3-94  2-6  7-13 
The  cytoplasm  stains  somewhat  deeply  and  is  free  from  granules  ; 
vacuoles  situated  close  to  the  blepharoplast  were  seen  in  two  or 
three  specimens.  The  blepharoplast  is  small  and  placed  close  to  the 
extremity ;  the  nucleus,  relatively  large,  stains  deeply  and  measures 
from  2'2  5  to  3  yu  in  length  and  from  i  to  1-5  yti  in  breadth.  In  most 
individuals  it  is  oval  or  drawn  out,  but  in  some  it  was  almost  rounded. 
There  is  practically  no  undulating  membrane ;  and  these  forms  are 
devoid  of  any  free  flagellum. 
The  original  sheep  of  this  strain  when  examined  in  May,  and 
from  August  up  to  its  death,  showed  only  the  long  forms.  This 
form  re-appeared  in  Sheep  i  on  inoculation,  and  remained  present 
until  September  30th.  Between  that  date  and  October  loth  no 
trypanosomes  were  seen  in  this  animal,  but  on  their  re-appearance 
they  were  practically  all  of  the  short  tadpole  variety.  A  careful 
examination  of  some  of  our  films  shows  that  in  Sheep  i  prior  to 
September  30th  one  or  two  tadpoles  were  present,  and  a  long  form 
has  been  seen  since  October  loth.  In  the  sub-inoculation  made  on 
what  proved  to  be  the  last  day  of  the  period  of  absence,  the  tadpole 
form  re-appeared  in  Sheep  4,  and  is  the  form  which  was  present  at 
the  last  examination  in  Pretoria,  January  20th. 
The  other  sheep  and  the  goat  at  Scotsdale,  and  the  sheep  at 
Kasama,  showed  the  long  form ;  but  an  occasional  tadpole  was 
seen ;  in  the  cattle  at  Scotsdale  and  Chinsali  none  but  tadpoles  were 
found  in  the  peripheral  blood. 
