PLASMA-STRUCTURE IN EGG OF HYDRACTINIA 209 



while the nucleus is unstained. Auerbach'sstain, which combines 

 acidulated methyl-green and acid fuchsin, also gives similar results 

 since the granules take the green basic stain and the nucleus 

 stains with the red plasma stain. 



Since the above stains contain an acid, several of the more 

 usual basic intra vitam stains were now tried (neutral red, meth- 

 ylene-blue and dahlia) . Different results appeared immediately, 

 since both the granules and the chromatin are stained intensely 

 with the neutral red or the methylene-blue. A still different 

 result was obtained with dahlia, for while the nucleus is stained 

 intensely purple, the granules were but slightly tinged. 



Since Lee states that these intra vitam stains are harmful to 

 the cell and the results not trustworthy, some further tests were 

 made with some comparatively new stains (footnote 4, table 2), 

 which have been found by other workers to be perfectly harmless 

 to the cell and to stain chromatin (Kite '13). These give the 

 most striking results. Three stains were used; new methylene- 

 blue G.G., new methylene-blue R., and diamond-fuchsin. A 

 very dilute solution was made by adding a small amount of the 

 stain to sea-water containing Hydractinia eggs. After a few 

 hours the eggs were mounted in glycerine. Methylene-blue G.G. 

 and R. gave the most striking results, although diamond-fuchsin 

 gives convincing preparations. The nucleus in every case takes 

 the basic stain strongly while the pseudochromatin-granules are left 

 colorless. A noticeable difference in staining reaction occurs 

 between fixed and living material, for in living material the nucleus 

 stains in all stages with these basic stains while in fixed material 

 the nucleus in late stages stains only in acid stains. Since in 

 certain cases the granules in living material do not take the chro- 

 matin-stains, while the nucleus does, they cannot be the same as 

 the chromatin in the nucleus and are therefore not formed chro- 

 matin extruded from the nucleus. And since with a stain that 

 is acid, the staining reaction is reversed, i.e., the granules stain 

 with the basic dye and the nucleus is either non-staining or stains 

 lightly with acid stains, it seems probable that the presence of 

 the acid is the determining factor in this reaction. The same 

 explanation would hold for the behavior after many killing fluids. 



