THE MITOCHONDRIAL CONSTITUENTS OF PROTOPLASM. 



93 



am unable to determine. Thus, the specificity of janus black is undoubtedly due 

 to the fact that it contains janus green as one of its ingredients. 



I have isolated the diethylsafranin from janus blue, janus black, and janus 

 gray (I failed with janus yellow, which may not contain it), and they all stain 

 mitochondria, which is further evidence that the specificity of janus green depends 

 upon the diethylsafranin group. It may be said that the staining is favored by 

 the addition of azodimethylanilin to it, as in janus green; increased, though not 

 so much so, by adding B-naphthol; and altogether prevented by the addition of 

 other groups, as in janus gray. 



I have made an attempt to compare the specificity of janus green for mito- 

 chondria with other dyes which investigators have made use of for the purpose of 

 staining them. I used living human lymphocytes in freshly drawn blood as mate- 

 rial. The results of the comparison are shown in table 3. The names of the dyes 

 are given in the left-hand column, the concentrations are noted above, and a few 

 notes are recorded on the right. Intense staining is designated #, a faint colora- 

 tion + , while the minus sign indicates that the mitochondria are entirely unaf- 

 fected. 



Table 3. — Sj>ecificalion of vital strainn. 



