354 
'atteignent  15  /i  a  17  de  long  sont  fort  rares ;  Tr.  dimorpkon 
‘  presents  an  contraire,  dans  les  cas  types,  un  melange  de 
‘  petites  formes  (10  /u  a  15  de  long)  et  de  grandes  (22  m  de  long  en 
‘  moyenne).  .  .  .  Mais  Tr.  dimorfhon  ne  se  presente  pas  toujours 
'  sous  ses  formes  typiques.  Dans  certaines  infections  dues  a  Tr. 
‘  dirnorphon,  les  grandes  formes  sont  rares  ou  tres  rares ,  si  bien  quon 
‘  pouvait  supposer  que  Tr.  congolense  etait  une  variete  de  Tr. 
‘  dimorphon  dans  laquelle  les  grandes  formes  avaient  disparu.  .  .  , 
and  as  further  substantiating  Broden’s  species  he  quotes  the  results 
of  *  cross  inoculations’  by  T.  dimorphon  {T .  conpusunT)  into  animals 
‘  immunised  ’  towards  T.  congolense.  These  observations  on  the 
morphology  are  in  entire  accord  with  those  of  Broden,  who  gives  a 
maximum  measurement  of  I5’5  /«  for  his  species. 
The  name  Trypetnosomu  congolcnss  cannot  then  be  applied  to  a 
form  which  under  the  normal  conditions  of  experimental  observation 
exceeds  about  17  /u  in  length;  it  differs  therefore  from  T.confusum, 
which  may  attain  23  or  24/1  but  which  does  not  develop  a  free 
flagellum,  and  from  T.  dimorphon,  which  in  certain  forms  resembles 
these  two  exactly,  but  which  is  capable  of  developing  a  distinct  free 
flagellum  upwards  of  lO  in  length.  The  parasite  which  Hohnel  has 
described  under  the  name  T.  congolense  would  appear  to  approximate 
more  closely  with  T.  con fu sum. 
The  trypanosome  from  Balungu  has  not  been  seen  to  exceed 
i6'3  /i  ;  until  further  investigation  decides  that  it  is  capable  of 
assuming  larger  dimensions,  m  which  case  our  conception  of  the 
classification  of  this  group  must  be  amended,  we  associate  it  with 
T.  congolense,  sensu  Broden  and  Laveran. 
B.  N inamwenda  strain. 
This  cow  came  to  Kambole  in  August,  190;,  from  the  Niamkolo 
Mission  on  Lake  Tanganyika,  a  place  where  cattle  appear  to  thrive 
and  where  no  sickness  is  recorded.  In  the  rainy  season  of  1907-1908 
she  became  extremely  emaciated  and  lost  practically  all  her  hair,  but 
regained  condition  and  coat  in  the  spring  of  1908.  At  examination 
on  October  ist,  she  was  not  particularly  thin,  and  was  said  to  be 
improving  ;  trypanosomes,  one  in  fifteen  fields,  were  seen,  and  they 
*  Broden.  Raf.  Lab.  Leopoldville,  No.  II,  igo6. 
