482 APPENDIX III. 



Eosin, Watery. Acts in much the same way. Also used to stain potas- 

 sium nitrate solution in plasmolysis studies, pp. 46, 253. 

 logwood ( Renaut's). Concentrated watery solution of eosin, 30 c.c., 

 saturated alcoholic solution of hsematoxylin, 40 c.c., glycerine 

 saturated with potassium-alum, 130 c.c. The solution should remain 

 unstoppered for some weeks till the alcohol has evaporated, and 

 should then he filtered. A good double stain for nuclear structure. 



Ether. As a reagent, used as a solvent for oils and eerie acid. Used also 

 to dissolve cake celloidin. See p. 400. Also in the identification of 

 Chitin in fungi, p. 239. 



F. 



'Fehling's Solution. For preparation, see p. 66. A reagent for glucose and 

 cane sugar. 



' Flemming's Solution or Fluid. See Chromosmium acetic acid. 



Fuchsin. Dissolved in half-and-half alcohol and water. Sections treated 

 previously with alcohol and stained with this, show up the structure 

 of thickened cell-walls. Stained, and washed in absolute alcohol, 

 the colour is removed from all excepting corky walls ; more briefly 

 washed, and controlled by careful watching, it is left also in lignified 

 membranes ; hence it can be used, e.g., with logwood, as an excellent 

 double stain. 



(Acid). Prepared by dissolving 0*2 per cent, acid fuchsiii in dis- 

 tilled water, and a little camphor added to make the solution keep. 

 A capital stain for chromatophores ; but it must be remembered that 

 it is soluble in alcohol, and this must not therefore be subsequently 

 used. 



iodine-green. Prepared by pouring a solution of iodine-green in 

 50 per cent, alcohol into a saucer, and adding fuchsin, also dissolved 

 in 50 per cent, alcohol, until the fluid takes a markedly violet 

 colour. This stain is very useful in vegetable histology. The 

 sections to be stained remain for about a minute in this solution, 

 and are then transferred to glycerine. Excellent for nuclear stain- 

 ing after Flemming's fluid. 



G. 



Gelatine. Used as a nutrient medium in cultivation of pollen-grains, 391, 

 and of bacteria, 283. 



'Gentian-violet. Very dilute watery solution, stains decolorised chlorophyll- 

 bodies, and other chromatophores, bacteria, spermatozoids, and the 

 nuclei of fungi. 



Acetic. Gentian-violet is dissolved in 1 per cent, solution of 

 acetic acid till the solution has a deep violet colour. A good nuclear 

 stain. 



These two stains are invaluable in preparations to show nuclear 

 figures. The stained preparations keep in glycerine. 



