404 
h3xlro]ysi.s,  p-amino-phenyl-arsenic  acid  and  salicylic  acid  would  be 
fomied.  The  salicylic  acid  might  then  act  as  an  internal  disinfectant. 
A  few  experiments  on  rats  infected  with  T .  brucei  showed  that 
doses  of  as  much  as  0’02  5  gm.  per  rat  of  about  170  gm.  did  not  cause 
a  disappearance  of  the  parasites  from  the  blood. 
3.  Formylo-Atoxyl. 
/**V  kJ 
Formylo-Atoxyl  brought  about  in  rats  infected  with  T.  evansi  a 
temporary  disappearance  of  the  parasites  after  two  to  three  injections 
of  0'02  5  gm.  ;  the  trypanosome,  however,  reappeared  in  the  course  of 
a  few  days.  The  drug  caused  abscesses  at  the  site  of  injection. 
4.  Sodium  p-hydroxy-phenyl-arsenate. 
OH 
This  compound  was  found  to  have  no  effect  whatever  on  the 
parasites,  a  fact  which  corresponds  with  the  view  that  the  presence  of 
the  amino  group  is  essential  for  a  trypanocidal  action. 
5.  Di-sodium  Azobenzene  4-arsenate 
^=A5  _ 
NaO-^ 
0>A5  _ 
Q 
and  Di-sodium  4-oxy  Azobenzene  4-arsenate. 
From  a  theoretical  point  of  view,  it  might  be  expected  that  after 
injection  both  compounds  would  on  reduction  in  the  organism  break 
