365 
healthy-looking,  except  the  spleen,  which  was  of  enormous  size  :  it  extended  right 
across  the  abdomen  and  measured  over  three  inches  in  width  at  the  narrowest 
part,  and  was  thickened  to  an  extent  of  nearly  two  inches  ;  the  substance  was  soft 
and  friable,  and  the  Malpighian  bodies  large  and  prominent. 
Experimental  infection 
The  following  inoculations  were  carried  out :  — 
ItAT  8. — October  30th,  1908.  Inoculated  subcutaneously  with  2-0  c.c.  blood 
of  ‘Dip.’  Trypanosomes  appeared  on  the  fifth  day  and  increased  in  numbers  to 
death  on  November  roth. 
Guinea-pig  10. — October  30th,  1908.  Inoculated  intraperitoneally  with  yoc.c. 
blood  of  ‘  Dip.’  No  trypanosomes  were  seen  up  to  November  15th.  They  were 
present  on  November  22nd  and  at  succeeding  examinations  to  death,  which 
occurred  on  December  7th  (38th  day). 
Guinea-pig  13.  December  7th.  Inoculated  intraperitoneally  with  1-50.0. 
blood  direct  from  Guinea-pig  10.  Trypanosomes  were  seen  on  December  12th  and 
the  animal  died  on  December  14th,  a  date  on  which  several  of  our  guinea-pigs 
died,  as  a  result,  we  think,  of  some  vegetable  irritant  in  the  food. 
Dog  12. — November  2nd.  Inoculated  subcutaneously  with  5-00.0.  heart  blood 
direct  from  ‘  Dip  ’  on  post-mortem.  The  temperature  rose  on  the  sixth  day,  and 
trypanosomes  were  present.  They  increased  in  numbers,  and  the  temperature 
continued  to  rise  up  to  death  on  November  13th,  the  eleventh  day. 
Dog  14. — ^Was  inoculated  subcutaneously  with  3*0  c.c.  blood  of  Dog  12  on 
November  13th.  No  trypanosomes  were  seen  up  to  December  7th,  when  he  was 
stolen  or  lost. 
Dog  15.. — Was  inoculated  subcutaneously  on  December  14th  with  2-0  c.c.  heart 
blood  of  Guinea-pig  13  immediately  after  death.  No  trypanosomes  were  ever  seen 
in  the  blood  of  this  animal,  which  arrived  in  Pretoria  looking  well. 
Morphology  of  the  ‘  Wallace'  Trypanosome 
In  fresh  preparations  the  actively  moving  organisms  remain 
localised  to  the  field  and  rarely  attempt  to  travel ;  they  recall  the 
forms  seen  in  Balungu  (Plate  IV,  fig.  4). 
Stained,  they  present  the  ordinary  appearance  of  a  ‘  tadpole  ’ 
trypanosome,  measuring  from  8'8  to  I5'3  p.  (average  I2'3  /x)  in  length, 
and  from  o'g  to  ryS  in  width.  The  following  is  the  mean  of  the 
measurements  :  — 
Nucleus  to 
flagellar  extremity 
5-8 
Extremity  to 
Nucleus 
4-+ 
Nucleus 
2-1 
The  small  blepharoplast  is  removed  a  short  distance  in  most 
individuals.  The  nucleus,  compact  and  deeply  staining,  is  oval  or 
compressed.  The  undulating  membrane  and  free  flagellum  are  absent 
or  very  rudimentary.  The  aflagellar  extremity  is  rounded  ;  in  some 
of  the  larger  forms  it  becomes  more  pointed. 
