Chapter VII 



67 — 



The Chondriome 



they stain selectively with Janus green, methyl violet 5B and 

 Dahlia violet. Recent research (Guilliermond and Gautheret) 

 has made known other vital dyes for staining chondriosomes : 

 gentian violet, crystal violet, Hoffman violet, methyl green, iodine 

 green, malachite green and Victoria blue. Among these, Janus 

 green is one of the least toxic. Used with Saprolegnia in weak 

 concentrations (0.0005-0.005% solutions) it stains only the chon- 

 driosomes, giving them a bluish green color in filaments which 

 continue to show strong cytoplasmic currents. Staining is there- 

 fore clearly vital. This vital staining of the chondriosomes by 

 Janus green is only transitory. It is observed that at the end 

 of a few moments the chondriosomes lose their green color, 

 whereas a rose tint appears in the vacuolar system. These ob- 

 servations are explained by the fact that the chondriosomes re- 

 duce Janus green to its rose derivative and this latter, having 

 more affinity than its oxidized form ^ 

 for the vacuolar system, diffuses i \^\/. • 

 into it. If higher concentrations of luj^/"^^) \ ^ 

 Janus green are used, it stains not j('\\(^,^^W^H-•^ 

 only the chondriosomes but also the b'^XlljKv^ 

 vacuolar system. The chondriosomes i \\f^ /3^^ 

 then remain colored but the filaments i[ 4\^> "pf '^i 

 die rapidly and do so generally with- 

 out reducing the dye. At concen- 

 trations above 0.005% the dye stains 

 the chondriosomes at first but rapid- 

 ly causes them to become vesiculate, 

 then accumulates in the vacuolar ^ „ „ , , ^, 



,, 1 1 j_ 1 • Fig. 32. — Portions of a filament of 



system as well, and later brmgS SavroUgnia, showing the similarity of 



about the death of the fungus. Most J^^) uying and (B) fixed tissue, in 



, the latter the hpide granules are 



of the other dyes, among them not visible, c, chondriosomes; cg, hp- 



methyl violet and Dahlia violet, are i^^^hoT""'^'' ^' ""*''^"'' ^^^""""^'^ 

 more toxic and stain living chondrio- 

 somes only in concentrations not exceeding 0.005%. At greater 

 strengths they stain the cytoplasm and nucleus as well as the 

 chondriosomes, which become vesiculate, and then very rapidly 

 bring about the death of the filaments. The attempts to grow 

 cultures of Saprolegniaceae in media to which vital dyes have 

 been added, has demonstrated the great toxicity of the dyes. It 

 has been possible, for example, to make one culture of Saprolegnia 

 grow in peptone bouillon containing up to 0.003% Janus green. 

 Under these conditions, it first reduced Janus green to its rose 

 derivative, which seems less toxic, and then developed without 

 showing any coloration whatever in its chondriosomes. With a 

 concentration of 0.004% Janus green, the fungus ceased to grow. 

 Dahlia violet and methyl violet proved even more toxic for this 

 same fungus which did not develop at all in a 0.001% solution of 

 this stain. 



The reagent iodine-potassium iodide preserves the chondrio- 

 somes perfectly. It makes them more yellow than the cytoplasm 



lu. V 



