347 
and  development  of  the  undulating  membrane,  recall  the  ‘  long  ’  form 
which  vve  figure  in  plate.  We  assume  from  Wenyon’s  remarks*  that 
both  ‘  short  ’  and  ‘  long  ’  occurred  simultaneously,  but  it  is  to  be 
regretted  that  a  more  detailed  account  of  these  experiments  and 
observations  was  not  published.  The  possibility  of  a  mixed  infection 
in  a  given  animal  is  manifest  in  a  trypanosome-infected  continent 
like  Africa,  from  which  already  T.  gambiense,  T.  evansi,  T.  briicei, 
T.  equiperdum,  T.  dimorphon,  T.  vivax,  T.  nanum,  T.  congolcnse, 
T.  cazalhoui,  T.  pecaudi,  and  T  sudanense\\^.\Q.  been  announced  in 
domestic  animals.  Still  greater  is  the  possibility  of  more  than  one 
species  occurring  in  any  given  herd  ;  one  has  but  to  review  the  recent 
publications  from  French  West  Africa  to  appreciate  this  fact,  and 
our  own  observations  at  Broken  Hill  and  at  Kambole  teach  the 
necessity  of  keeping  distinct  genealogical  records.  It  is  easy  to 
assume  the  identity  of  the  trypanosomes  in  the  case  of 
two  animals  infected  with  such  morphologically  similar 
trypanosomes  as  tadpole  T.  dimorphon  (sensu,  Dutton  and  Todd, 
1903),  and  tadpole  T.  nannm  {sensu,  Laveran  and  Balfour,  1905). 
Rats  are  inoculated  with  the  latter  with  negative  results ;  from  the 
former  an  inoculated  .sheep  is  used  for  all  subsequent  work,  the 
results  of  which  are  directly  opposed  to  those  previously  obtained, 
and  the  inevitable  sequel  is  that  considerable  confusion  occurs  in 
the  literature. 
The  precision  and  lack  of  confusion  regarding  trypanosomes 
which  have  been  studied  in  Europe — trypanosomes  taken  there  in 
individual  animals — or  in  Africa  where  morphology  and  diagnosis 
has  been  effected  by  the  animal  reactions  of  the  strain  from  one 
animal  alone  (e.g.,  the  original  T .  nanum  and  some  trypanosomes  of 
the  Sleeping  Sickness  Commission  in  Uganda),  contrast  forcibly  with 
the  chaotic  state  of  the  literature  concerning  other  African  trypano¬ 
somes  to-day. 
T .  nammi  was  constituted  on  the  morphological  observations  of 
Laveran  and  the  animal  reactions  noted  by  Balfour.  To  be  identified 
with  this  species,  a  trypanosome  must  conform  to  these  original 
descriptions  whatever  additional  features  are  brought  to  light  by 
subsequent  investigations. 
*  We  have  had  the  privilege  of  examining  some  of  Dr.  Wenyon’s  specimens. 
The  long  form  which  we  describe  is  morphologically  different. 
