55J 
OBSERVATIONS  ON  THE  LIFE  HISTORY 
OF  TRYPANOSOMA  LEIVISI  IN  THE 
RAT  LOUSE  (HAEMATOPINUS 
SPINUEOSUS) 
HV 
ANTON  BREINL 
AND 
EDWARD  HINDLE 
from  the  Runcorn  Research  Laboratories  of  the  Liverpool  School 
of  Tropical  Medicine 
\Received-  for  publication  26  October,  1909) 
For  over  a  year  we  have  carried  out  experiments  concerning-  the 
mode  of  transmission  of  Trypanosoma  leivisi  by  means  of  the  rat 
louse  Haematopmus  spinulosus.  Although  our  results  are  far  from 
complete,  circumstances  compel  us  to  abandon  this  research  for  the 
present. 
We  have  succeeded  in  transmitting  T.  lewisi  by  means  of 
Haematopmus  spinulosus,  and,  with  the  aid  of  wet  fixation  methods, 
m  modifying  conclusions  which  have  previously  been  drawn 
concerning  the  cytological  characters  of  this  parasite  in  specimens 
stained  by  Romanowsky.  We  do  not  intend  in  the  present  paper  to 
go  into  a  detailed,  theoretical  discussion,  which  we  reserve  for  a 
future  communication,  but  only  to  bring  forward  some  new  facts  and 
observations  concerning  the  life-history  of  T.  leivisi  in  its  intermediate 
host. 
Prowazek^  was  the  first  to  draw  attention  to  the  life-history  of 
T.  leivisi  in  the  rat  louse.  For  some  years  Prowazek’s  conclusions 
were  generally  accepted,  without  being  confirmed  by  other  workers. 
Patton’s  and  Strickland’s^  attempt  to  confirm  Prowazek’s  work  led 
them  to  the  conclusion,  that  Prowazek  had  described  part  of  the  life 
cycle  of  a  natural  fiagellate,  Critkidia  sp.,  of  Haematopmus 
spinulosus,  which  they  believe  has  no  connection  with  7'.  lewisi. 
