STAIN TECHNIQUE 55 



Small invertebrates are mordanted for 30 minutes in 1 per cent 

 ferric ammonium sulfate. After a rinse in distilled water, the 

 material appears blue-black after one or two minutes in the stain 

 at 50° C. With copper acetate as the mordant the color is Hema- 

 tein-purple. Paraffin sections of animal tissues are stained violet 

 with blue-black nuclei in 15 to 30 seconds at 50° C. 



Paraffin sections of plant tissues mordanted in ferric alum and 

 kept for five to ten minutes in the dye at 50° C. become reddish vio- 

 let in the cytoplasm to blue-violet in the nuclei. With this dye in 

 dilute sulfuric acid, the sections mordanted in iron alum take a blue 

 nuclear stain. Whole mounts take on a Hematein-purple of ex- 

 cellent fastness. Blue-green algae are readily stained without the 

 aid of a mordant. 



783. Cerulein MS, Anthracene Green, Coerulein MS is a mor- 

 dant dye, light 3 to 4; J gram in 100 ml. of 1 per cent ammonium 

 acetate. This dye does not give a satisfactory stain on animal tis- 

 sues. Vascular plant tissues mordanted in ferric alum become dull 

 green in the stain at 50° C. In alkaline solutions of the dye blue- 

 green algae are clear green. 



Class XII. Acridine Colouring Matters 



785. Acridine Yellow R, 2R is a basic dye, light 2; £ gram in 

 95 ml. of distilled water, 5 ml. of 5 per cent ammonium alum, and ■£■ 

 ml. of acetic acid. Unless the stain contains ammonium alum, the 

 dye bleeds from sections mounted in balsam ; more than the usual 

 amount of time is needed for dehydration. The dye may be used 

 in preference to Bismarck Brown, C. I. No. 331. 



788. Acridine Orange is a basic dye, light 1 to 2 ; £ gram in 95 

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

 of acetic acid. Plant tissues are stained a clear brown or dark 

 orange of exceptional fastness. To prevent bleeding of the color 

 in balsam, dehydrate the material slowly. 



793. Phosphine is a basic dye, light 2 to 3. This dye is a by- 

 product obtained in the manufacture of Basic Fuchsine. The stain 

 is similar in color to Acridine Orange but not of equal fastness. 

 The dye-solution decomposes on standing. 



