407 
the  other,  105  days  after  discontinuance  of  treatment  (o‘o6  gm.  of 
Orsudan  was  administered  in  three  injections). 
Out  of  twelve  rats  infected  with  2\  garnbiense  one  lived  for  165 
days,  one  for  1 1 5  days  (both  dying  without  having  shown  parasites  in 
the  blood),  and  one  had  a  relapse  fifty  days  after  the  last  injection. 
Guinea-pigs  infected  with  T.  garnbiense  stood  Orsudan  much 
better  than  Atoxyl.  The  parasites  always  disappeared  from  the 
blood  after  the  first  injection  of  0'025  gm.  When  the  treatment 
was  discontinued,  relapses  set  in  after  a  varying  interval.  If  treat¬ 
ment  was  continued  the  intervals  between  the  relapses  became  shorter 
and  shorter,  until  a  point  was  reached  when  even  repeated  injections 
had  no  effect  on  the  parasites,  and  the  animal  succumbed  to  the 
trypanosome  infection.  If  the  parasites  were  subinoculated  into 
guinea-pigs,  one  injection  of  Orsudan  was  sufficient  to  drive  out  the 
parasites. 
Three  donkeys,  infected  with  T .  equiperdum,  were  treated  with 
Orsudan.  Two  died  after  two  injections  (each  of  one  gramme)  after 
typical  symptoms  of  arsenic  poisoning  lasting  three  days.  The 
internal  organs  showed  fatty  degeneration  of  the  liver  and  kidneys. 
One  donkey  died  of  Trypanosomiasis  227  days  later.  It  received, 
during  this  period,  nine  injections,  each  of  one  gramme  of  Orsudan  ; 
parasites  in  small  numbers  were  occasionally  seen  in  the  blood. 
Four  monkeys  infected  with  T.  garnbiense,  after  the  infection 
was  well  established,  were  treated  with  Orsudan.  One  Cercopithecus 
callitrichus  died  with  all  the  symptoms  of  typical  arsenic  poisoning, 
after  having  received  O’ 2  gm.  in  two  injections.  One  Cercopithecus 
mona  received  0’2  gm.  in  two  injections,  and  had  a  relapse  forty-nine 
days  after  the  last  injection.  The  treatment  was  repeated  with 
O'  I  gm.  of  Orsudan.  Although  symptoms  of  arsenic  poisoning  set  in 
a  few  days  afterwards,  they  passed  off  in  a  week,  and  the  animal 
lived  for  254  days  in  good  health  without  showing  any  parasites.  On 
reinoculation  of  T .  garnbiense  it  succumbed  to  the  infection. 
One  Cercopithecus  callitrichus  received  o’2  gm.  of  Orsudan  in 
two  injections.  Three  days  afterwards  severe  symptoms  of  arsenic 
poisoning  set  in,  which,  however,  passed  off  in  a  week’s  time.  Twenty- 
five  days  afterwards  treatment  was  resumed  with  one  injection  of 
O’ I  gm.  Orsudan.  Two  days  afterwards  symptoms  of  arsenic 
poisoning  commenced  ;  four  days  later  failure  of  eyesight  was  noticed, 
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