814 



SCIENCE 



[N. S. Vol. XXXII. No. 832 



injection of which caused the disappear- 

 ance of the parasite — was the best agent 

 for the treatment of nagana, mal de cad- 

 eras and surra. On the other hand, a color 

 derived from paradiaminodiphenyl-urea 

 and the above-mentioned acid acted better 

 than the latter color in the treatment of 

 recurrences of the parasites, although a 

 single injection of it never caused their 

 complete disappearance. 



Mesnil and Nicolle then undertook some 

 investigations on monkeys which had been 

 inoculated with the parasite of sleeping 

 sickness, and found that the correspond- 

 ing color from paradiaminodiphenyl-urea 

 acted best in these cases. They believed, 

 however, that in human beings the condi- 

 tions for a cure were much more unfavor- 

 able, because the patients generally came 

 under observation at a much later period. 

 They also proved that atoxyl was especially 

 useful and recommended the combined use 

 of these substances. 



The following structural formula will 

 give a picture of the relation of the various 

 classes of colors employed: 

 Benzidin : 



Benzidinmonosulfoacid : 



SO3H 



^ , I 



NH,-/^\_/ \_NH, 



Naphthylamin disulfo acid: 



SO,Na- 



Trypanred ; 



-SO,Na 



Diamidonaphthalene disulfo acid 



(2.7.3.6.) : 



NH,-,<i 



-NH, 



rK_>-<_>-y 



SOaNa-l I l-SOsNa SOsNa- 



Amidotrypanred (unsymmetrical) : 

 SO3H 



rKi>-<z>=y 



^^H^—/ \/ \,— NHo NH2— 1''''\/\ 



SOaNa-l^^-SOsNa SOaNa-l Ij-SOsNa 



Amidonaphtholdisulfo-acid 1.8.3.6. 

 (called Acid H) : 



NH, OH 



Orthotolidin : 



CH3 CH3 



CH3— I i OH NH. 



N=N {\\ 



SOjNa— ' I I SOaNa 

 Dichlorbenzidin : 



CI CI 



/-NH, 



Azodyestuffs with Acid H: 



(1) Alkaline combination liquid: 



