Decembeb 9, 1910] 



SCIENCE 



813 



in practical medicine. In this country A. 

 Jacobi has particularly called attention to 

 this quality of the color and to its value in 

 the treatment of inoperable cases of cancer. 

 Later Ehrlich, in conjunction with Gutt- 

 mann, experimented with methylenblue in 

 malaria, and found it a true specific for 

 the parasite of the quartan type of the 

 disease, while it acted less promptly or 

 failed in other varieties. In view of the 

 difSculty, however, of experimenting with 

 malarial organisms he found the trypano- 

 soma much better adapted for his studies, 

 since it can be inoculated in small animals, 

 such as mice and rats. Since 1904, with 

 the assistance of K. Shiga, he has tested 

 man}' hundreds of various colors in order 

 to determine their influence upon trypano- 

 soma infection, and finally found among 

 the benzidin group a color which, when ad- 

 ministered to mice inoculated with the 

 trypanosoma of mal de caderas, retarded 

 the progress of the malady for several 

 days. This result, though not decisive, 

 was sufSciently promising to lead him to 

 experiment with other synthetic products 

 of the benzidin group. He finally discov- 

 ered trj'panred, which was found to exert 

 an actual curative effect upon the above- 

 mentioned trypanosoma. "When trypanred 

 was injected into mice twenty-four hours 

 after they had been infected with the 

 trypanosoma of mal de caderas, which 

 ordinarily produced death in four to five 

 days, it was noted that on the following 

 day the parasites had disappeared com- 

 pletely from the blood, and the majority 

 of the animals remained permanently 

 cured. Sometimes, however, the parasites 

 reappeared after a number of weeks, and 

 then speedily caused the death of the 

 animal. 



These results were confirmed by Laveran 

 and Halberstaedter with other parasites. 

 The former inoculated mice with the para- 



site of mbori, the latter with the parasite 

 of dourine. 



Ehrlich 's experiment therefore was the 

 first which clearly showed that it was pos- 

 sible by means of an anilin color to free 

 the body entirely of virulent parasitic or- 

 ganisms. Curiously enough, however, the 

 trypanred which acted so efficiently in this 

 respect in mice inoculated with trypano- 

 soma of mal de caderas, had a much less 

 favorable effect in other species of animals, 

 even the rat, and against other varieties of 

 trypanosoma, as, for instance, that of tsetse 

 disease. On the other hand, Laveran and 

 Franke showed that by combining arsenous 

 acid with trypanred a curative effect could 

 be obtained in conditions unaffected by the 

 latter alone. 



In order to improve trypanred, Ehrlich, 

 together with Weinberg, tested a large 

 number of substitution products of this 

 substance, and found among them an 

 amidotrypanred, which acted more effi- 

 ciently than trypanred itself upon the 

 virulent nagana parasite. 



Mesnil and NicoUe, of the Pasteur Insti- 

 tute of Paris, continued Ehrlich 's experi- 

 ments with a large number of synthetic 

 colors. Their first experiments were un- 

 dertaken with a number of benzidin colors, 

 the parasite selected for the test being the 

 trypanosoma of nagana, the tsetse fly dis- 

 ease. This parasite was chosen because it 

 is more refractory to trypanred than some 

 of the others. These experiments, which 

 were made upon mice, showed that certain 

 blue or violet colors derived from 1.8 

 amidonaphthol 3.6 disulfo acid, especially 

 the combination with orthotolidin in alka- 

 line liquid, trypanblue acted more effi- 

 ciently than trypanred. They further 

 found that the azo dyestuff prepared from 

 dichlorbenzidin and the above acid in alka- 

 line combination — a color which produced 

 intense staining of the tissues, and a single 



