397 
experimental  Trypanosomiasis  with  a  view  to  administering  arsenic  in 
larger  doses  and  in  a  less  toxic  form  than  sodium  arsenate,  which  was 
already  known  to  possess  a  specific  action  on  T.  brucei. 
Theii  work  was  continued  by  Moore,  Nierenstein  and  Todd,*  who 
concluded  that  the  specific  action  of  Atoxyl  on  trypanosomes  can  not 
only  be  explained  on  the  assumption  of  a  slow  breakdown  of  Atoxyl 
into  an  inorganic  arsenical  and  aniline  ion,  but  is  also  ‘  due  to  direct 
and  specific  action  of  a  complex  organic  ion  containing  both  the 
aniline  and  arsenical  groups.’t 
Mesnil  and  Brimont*  explain  the  action  of  Atoxyl  on  trj  panosomes 
m  a  similar  way.  Their  conclusions  are  based  on  the  observation  of 
a  specific  lesistance  of  trypanosomes  to  drugs  of  the  same  type,  but 
not  to  those  of  different  types,  such  as  parafuchsin  on  the  one  hand 
and  Atoxyl  and  acetylated  Atoxyl  on  the  other  hand,  a  fact  which 
proves  que  1  atoxyl  n’agit  pas  uniquement  comme  arsenical,  mais  en 
vertu  d’un  ion  complexe.’ 
Uhlenhuth  and  M'oithe§  incline  to  this  view,  as  the  symptoms  in 
experimental  animals  caused  through  toxic  doses  of  Atoxyl,  are  not 
those  of  either  aniline  or  arsenic  poisoning.  They  ‘  beziehen  diese 
ganz  besonders  gearteten  neia^osen  S3-mptome  auf  den  ganzen  7\tom- 
coniplex  des  Atoxyls.’  The  Atoxyl  as  such  has  a  specific  action  on 
the  cells  of  the  organism,  after  the)-  have  undergone  a  change  in  some 
way  or  other  under  the  infiuence  of  the  parasites.  This  hypothetical 
action  on  the  cells  results  in  an  increased  formation  of  specific  anti¬ 
bodies,  which  still  continues  even  after  the  Atoxyl  has  been  eliminated 
from  the  organism.  These  antibodies  destroy  the  greater  number  of 
the  parasites  and  prevent  the  few  surviving  trypanosomes  from 
multiplying  and  injuring  the  host.^ 
*  [a]  Moore,  Nierenstein  and  Todd. 
[b\  Moore,  Nierenstein  and  Todd, 
■sitology,  Vol.  ir.  No.  4,  1909. 
t  -Moore,  Nierenstein  and  Todd. 
P-  3^2,  J907. 
Bio-chemical  Journal,  Vol.  II,  No.  4-5,  1907. 
Annals  of  Tropical  Medicine  and  Para- 
Bio-chemical  Journal,  Vol.  II,  No.  4-5, 
JMe.snil  and  Brimont,  Comptes  Kendus  de  la  Soc.  de  Biol.,  Tome  TXI\' 
p.  639. 
Uhlenhuth  und  Woithe.  Arb.  aus  dem  Kaisl.  Oesundheitsamte,  Band  XXl.V. 
190S.  Reprint  p.  34. 
^Uhlenhuth  und  Woithe.  Arb.  aus  dem  Kaisl.  rTe.sundheitsamte,  Bd.  XXVTI 
-  nett,  1907.  ^ 
