Dkcembeb 9, 1910] 



SCIENCE 



817 



This feeding method seemed also most 

 suitable for human beings, as injections 

 would be too painful, 1 gm. fuchsin base 

 daily being considered a proper initial 

 dose. In giving parafuchsin internally it 

 was suggested that the dose should be as 

 large as possible, and that this treatment 

 might be combined with the administra- 

 tion of atoxyl or some other drug. Ehrlich 

 further proposed feeding with fuchsin as 

 a preventative measure for people travel- 

 ing through regions where sleeping sick- 

 ness prevails. 



More recently most excellent results 

 were obtained by employing instead of the 

 above parafuchsin, chlorinated parafuch- 

 sin, which is known as " tryparosan. " 



The following formula will facilitate a 

 review of the colors experimented upon by 

 Ehrlich : 

 Methylenblue : 



(CH3),N.CeH3^ \CeH3N(CH3), 

 Malachitegreen : 



/CeH,-N(CH3), 



XH, : N(CH3),C1 

 Brilliant-green : 



/CeH,N(C,H,), 

 ^CsH' : N(C2H5),HSO, 



Hexamethyl violet (completely substituted) 

 (Crystalviolet) : 



/C„H,-N(CH,), 



^C6H,N(CH3),-C1 

 Tritolj'lrosanilin (New fuchsin) : 



c/_C.H3<f^' 



\ 





CI 



/C.H,N(CH3), 

 H0-C^C,H3<g^0^ 



2. Chromeblue: 



/QH,N(CH3), 



\ 



COOH 



:QH, : N(CTI3),.C1. 



3. Azogreen: 



/CeH.N(CH3), 



H0-C^-C6H,N=N • C8H3/ 



\ N:OOH 



XH,N(CH3), 



4. Pararosanilin (parafiichsin) : 



C-CeH,.NH, 

 SCeH, : NHjCl 



5. Ortho-tri-oxy-hexa-methylpara-rosani- 



lin: 



.OH 



/ \N(CH3), 



C CeHj/ 



\ \N(CH3), 



~^c„a 



\7« 



■ ci 



Carboxj-l derivatives : 

 1. Chrome violet: 



^N(CH3), 



Besides these colors Ehrlich investi- 

 gated representatives of other groups of 

 coal-tar colors, but found them inferior to 

 those described. 



The amount of work done by him can 

 hardly be realized. It must be considered 

 that many of the colors used had to be 

 synthetized, as they were not commercial 

 articles; they had then to be tested for 

 toxicity on various species of animals, and 

 finally their effect on trypanosoma had to 

 be established. Of the immense material 

 investigated only about ten substances 

 stood the test. 



There can be no doubt that thus far 

 atoxyl has proved the most effective 

 remedy for sleeping sickness, as it fre- 

 quently causes marked improvement even 



