399 
They  assume  in  the  protoplasm  of  the  trypanosome  the  existence 
of  a  special  chemical  complex  (Arseno-receptor)  which  possesses  a 
great  affinity  for  tri valent  arsenic. 
Ehrlich's  theory  led  to  Levaditi’s  and  Yamanouchi’s* * * §  studies  on 
the  mechanism  of  the  action  of  Atoxyl.  By  the  action  of  an 
emulsion  of  animal  tissue,  especially  liver,  they  were  able  to 
transform  Atoxyl,  which  is  inactive  in  vitro,  into  a  trypanocidal 
compound  ‘  trypanotoxyl,’  which  they  regard  as  a  combination  of 
reduced  Atoxyl  with  protein,  a  ‘  toxalbumine  arseniee  ’  of  a 
tliermolabile  character.  Levaditi  compares  this  ‘  toxalbumine 
arseniee  ’  with  a  haemolysin  ;  the  arsenic  plays  the  part  of  a  comple¬ 
ment  ;  the  protein  nucleus,  the  role  of  an  amboceptor.  The  arsenic, 
therefore,  cannot  attach  itself  to  the  trypanosomes  without  the  inter- 
currence  of  the  protein  nucleus  of  the  toxalbumine  arseniee.f 
In  a  somewhat  different  way  Fricdberger^:  succeeded  in 
transforming  Atoxyl  into  a  trypanocidal  compound  in  vitro  by 
adding  thioglycolic  acid  to  a  solution  of  Atoxyl.  The  leading  idea 
in  his  experiments  was  Eleffter’s  theory  of  the  reductive  properties  of 
the  organism  ;  according  to  the  latter  the  protein  ‘  reductases  ’  arc 
not  to  be  considered  living  ferments,  but  the  reduction  is  brought 
about  by  sulphhydryl  or  SIT  groups  which  also  are  present  in  this 
glycolic  acid. 
Our  experiments,^  however,  have  brought  forward  very  little 
evidence  for  the  supposition  that  a  reduction  process  in  the  organism 
plays  a  prominent  role  in  the  action  of  Atoxyl  on  trypanosomes.  As 
a  matter  of  fact,  all  our  results  tend  to  show  that  the  transformation 
of  Atoxyl  into  a  powerful  trypanocide  in  vitro  and  in  vivo  is  mainly 
*  («)  Levaditi  et  Yamanouchi.  Comptes  Rendus  de  la  Soc.  de  Biol.  Tome  LX\  , 
p.  23.  190S. 
(b)  Levaditi,  Brimont  et  Yamanouchi.  Comptes  Rendus  de  la  Soc.  de  Biol., 
Tome  LXV,  p.  25,  1908. 
(f)  Levaditi.  Bull,  de  la  Soc.  de  Rath,  exotique,  Tome  II,  p.  45-  i9°9- 
{d)  Levaditi.  Comptes  Rendus  de  la  Soc.  de  Biol.,  Tome  LXVI,  p.  33,  1909. 
[e]  T.evaditi.  Comptes  Rendus  de  la  Soc.  de  Biol.,  Tome  LXVI,  p.  492,  1909. 
i  Rdhl  in  a  more  recent  publication  (Zeitschrift  f.  Immunitatsforschung. 
Vol.  II,  p.  496,  1909),  points  out  that  Levaditi  does  not  furnish  any  conclusive 
jiroof  for  his  conception  of  the  formation  of  trypanatoxyl  in  the  orgariism,  and 
asserts  that  the  trypanocidal  effect  of  Atoxyl  t>i  vivo  is  onlj'  due  to  the  formation 
of  p-amino-phenyl  arsenoxide. 
I  Friedberger.  Berl.  kliii.  Wochenschrift  No.  38,  1908. 
§  Breinl  and  Nierenstein.  Zeit  f.  Immunitatsforschung,  etc.,  \ol.  I,  p.  620, 
BE 
