410 
The  preparation  of  trypanred  by  Ehrlich  and  Shiga  (Formula  1) 
-N= 
HgN/ 
^N=  N  - 
NH2 
oo 
SO3  14  <a 
NaO^: 
S03Na 
NaOg  S 
has  led  to  the  discovery  of  afridol  blue  by  Nicolle  and  Mesnil 
(Formula  II). 
H^N  OH  NH2 
,co 
00 
,00 
-N  =  N- 
-  N=  N- 
HSO 
O3SH 
HO3S 
sq^hX/ 
Afterwards  Ehrlich  introduced  parafuchsin  (Formula  III)  and 
tryparosan,  a  chlorinated  parafuchsin,  m  the  treatment  of  experi¬ 
mental  trypanosomiasis. 
NfCHa)^ 
The  value  of  all  these  colouring  matters  has  been  put  to  a  severe 
test  in  this  laboratory,  but  with  discouraging  results.  Thomas  and 
Breinl'’'  in  1905  remarked  in  reference  to  trypanred,  ‘that  we  cannot 
claim  to  have  cured  any  animal  infected  with  the  parasites  of  surra, 
ngana  and  dourine.  The  disease,  especially  in  rats  and  mice,  may  be 
greatly  prolonged,  but  the  animals  eventually  die.’  Moore, 
Nierenstem  and  Toddt  came  to  a  similar  conclusion  ‘that  trypanroth 
was  not  always  able  to  prevent  an  early  death  from  the  disease.’ 
Afridol  blue  and  parafuchsin,  phosphines  and  numerous  other 
colouring  matters,  had  in  our  hands  only  a  slight  effect,  or  no  effect  at 
all,  on  the  parasites.  We  may  say  that  hardly  any  work  with  these 
*  Thomas  and  Breinl.  Liverpool  School  of  Tropical  Medicine,  Memoir  XVI, 
p.  51,  1905. 
t  Moore,  Nierenstein  and  Todd.  Annals  of  Trop.  Med.  and  Parasitol., 
V'ol.  II,  No.  4,  p.  285. 
