58 W. H. E M I G 



of 50 per cent alcohol and J ml. of acetic acid. The nuclei of paren- 

 chyma are stained bright red ; the cytoplasm and cell walls, fuchsia. 



860. Acetin Blue R, Induline alcohol soluble, is a basic dye, 

 light 4. Plant tissues in paraffin sections are stained a dull light 

 blue. 



861. Induline water soluble is an acid dye, light 4 to 5. Plant 

 tissues are stained light blue in acid solutions of the dye or black 

 with the addition of potassium dichromate. 



865. Nigrosine water soluble is an acid dye, light 3 to 4. Pa- 

 renchyma is stained dull blue in an acid solution of the dye. With 

 potassium dichromate present the cell walls are blue ; the nuclei re- 

 main unchanged or yellow-brown. 



Class XVIII. Aniline Black and Allied Colouring Matters 

 Class XIX. Oxazine Colouring Matters 



876. Capri Blue is a basic dye, light 3 ; 1/10 gram in 95 ml. of 

 distilled water, 5 ml. of 5 per cent ammonium alum, and -J ml. of 

 acetic acid. Plant tissues are stained blue or black. This dye may 

 be used in preference to Cyanine, C. I. No. 806; it should counter- 

 stain well after Erythrosin, C. I. No. 773. 



877. Brilliant Cresyl Blue, Brilliant Blue is a basic dye, light 

 3. Certain plants in whole mounts are stained blue but the color is 

 not of uniform density. 



883. Gallocyanine is a direct mordant dye. The pigment ob- 

 tained at room temperature is fugitive, light 4. At 50° C. the color 

 is intensified to a deep blue-black with an increase in fastness to that 

 of the best dyes, light 1 ; 1/10 gram in 100 ml. of 1 per cent am- 

 monium acetate. 



Invertebrates are placed in 1 per cent ferric ammonium sulfate 

 for 30 minutes. After a rinse in distilled water, the material, at 

 50° C, becomes a Hematein-purple in one or two minutes. Paraffin 

 sections of animal tissues are violet within 30 seconds. Plant mate- 

 rials mordanted in ferric alum require five to ten minutes for whole 

 mounts or 15 to 20 minutes on paraffin sections. 



909. Meldola Blue is a basic dye, light 4 to 5. The dye is 

 somewhat selective in that the nuclei are stained blue-black and the 



