ZOOLOGY AND BOTANY, MICBOSCOPY, ETC. 1057 



perfectly normal, there being no distortion or change beyond the change in 

 colour. As yet he has not studied especially what parts of the nucleus are 

 coloured, but it appears to be the nucleolus and microsomes only, as in the 

 case of cells that have first been killed and then stained according to the 

 ordinary methods. 



Among other objects that have given more or less satisfactory results 

 were the hairs from the base of the perianth of Liliiim hulbiferum, stamen 

 hairs of ApJiodelus alhus, leaves of Elodea Canadensis and Vallisneria spiralis, 

 root-hairs of Trianea Bogatensis, Cucurhita Pepo, Tradescantia zehrina, 

 spermatozoids of Cha7-a and a fern (probably Blechnum). In all cases cells 

 were chosen in which there was evident protoplasmic movement, in order 

 that there might be a certain means of determining whether or not the cell 

 was still living. 



Similar and usually quite as good results were also obtained with mauvein 

 and methyl- violet, both colours closely resembling dahlia. Usually a 1 per 

 cent, solution was made, and this diluted with from 50 to 1000 parts of 

 water, according to circumstances. Some doubtful results were obtained 

 with other colours, but too uncertain to warrant recording. 



Absorption of Anilin Colours by Living Cells.* — Eeferring to Pfeffer's 

 experiments showing that, contrary to the ordinarily accepted idea, various 

 anilin coloui-s can be absorbed in large quantities by living cells, 

 Mr. D. H. Campbell calls attention to some easily made but instructive 

 experiments bearing on the subject. 



Pfeffer's experiments were mostly made with methylen-blue and methyl- 

 violet, though numerous other colours were also tried. Among colours not 

 employed by him, the author found that dahlia and mauvein, both very 

 similar to methyl-violet, were quite as good, and acted much in the same 

 way. The yellow colour chrysoidin also gave good results. No very satis- 

 factory results were obtained with red pigments, though in some cases 

 safranin, tropseolin, and fuchsin gave tolerably good colouring, but either 

 it was too diffuse or the cell-wall was more deeply coloured than the 

 contents. 



With methylen-blue either the cell-sap is coloured, often very intensely, 

 e. g. root-hairs of Trianea Bogatensis, or a precipitate is formed in the cell- 

 sap, e. g. Spirogyra. If vesicles of tannic acid are present, as is the case 

 in Zygnema, these are coloured dark blue. Methyl-violet, dahlia, and 

 mauvein colour the protoplasm and nucleus, and are specially valuable in 

 the study of the latter. In some cases they are also precipitated in the cell- 

 sap. Chrysoidin appears to colour only the protoplasm. The following 

 are some of the objects that were used : — Eoot-hairs of Trianea Bogatensis, 

 Cucurhita, Tradescantia zehrina ; stamen-hairs of various species of Trades- 

 cantia ; Spirogyra spp., Zygnema spp. ; roots of Lemna minor ; leaves of 

 Elodea (^Anacharis) Canadensis, Vallisneria spiralis ; pollen-tubes of Hemero- 

 callis spp., Tradescantia Virginica, Scilla spp, ; spermatozoids of Chara. 



The objects are placed in a solution of • 002-0 • 001 per cent., varyincr 

 with the nature of the cell-wall and the time of immersion. Eoot-haii-s are 

 usually especially delicate, and the solution should be very dilute or the 

 immersion very brief. 



In most cases objects were selected where there was marked protoplasmic 

 streaming, as this is the best means of determining whether the cell is alive 

 or not. It is surprising how deeply the protoplasm or nucleus may be 

 stained without materially affecting the streaming. For a demonstration of 

 the staining of the protoplasm the root- hairs of Trianea were found to be 



* Bot. Gazette, xii. (1887) pp. 193-4. 



