Effect of Gentian Violet on Protozoa. 123 



thelial cells from the peritoneum of the female frog, which had 

 been lying in stained plasma for five days. 



The growing cells seemed to have the power of gradually 

 changing the stain so that its color fades. That a similar change 

 takes place in the animal body was pointed out in an earlier 

 communication. 1 It was there shown that large amounts of 

 gentian violet injected into the ear vein of the rabbit soon dis- 

 appeared from the blood and that the mucosa of the tongue and 

 lips, though at first deeply stained, in a short time (about 48 hours) 

 lost their violet color. Animals killed a few days after the injec- 

 tion showed no trace of the dye, nor did it appear in the urine. 

 Attention was called in this paper to the care which must be used 

 in speaking of the non-toxicity of this and other dyes; for, as was 

 there suggested, the tolerance of the dye by the animal might 

 have been due to the animal's ability to change the substance into 

 another actually non-toxic one. 



In the original communication on the selective bactericidal 

 action of gentian violet the suggestion was made that similar 

 studies should be carried out on the effect of the dye on growing 

 tissue. This communication contains the first report of work 

 undertaken in that direction, which is still being prosecuted in this 

 laboratory. We have also under way an investigation of the effect 

 of gentian violet and other dyes on growing embryonic tissue from 

 the tadpole. The significance of the results thus far obtained 

 seems to us to be: 



1. The successful growth of tissue in stain-containing media 

 suggests the possibility that stains may be found which have a 

 selective action on tissue, similar to that pc«sessed by gentian 

 violet for bacteria; and that in this way pure cultures of tissue 

 may be possible out of mixtures, just as pure cultures of bacteria 

 may now be so obtained. 



2. Certain animal tissues grow readily in gentian violet of a 

 far stronger dilution than that necessary to kill many contaminat- 

 ing bacteria. In these experiments, for example, successful tissue 

 growths were obtained when gentian violet, 1 to 20,000, was used; 

 yet bacillus subtilis will not grow in 1 to 100,000 and grows very 

 badly in 1 to 1,000,000. This fact may simplify the technique 

 of tissue growth by eliminating the risk of bacterial contamination. 



1 Churchman and Herz, Journ. Exp. Med., Vol. XVIII, No. 5, 1913. 



