the nucleus is arranged in a spoke-like fashion (' rad- 

 kern '). The nucleus is at one side of the cell and is 

 separated from the cytoplasm by a halo. 



The leucocytes may be studied and counted in films 

 stained with Romanowsky, but for many purposes it is 

 advantageous to use one or more of the following stains. 

 For studying the character of the nuclei, haematein is 

 the best; for the granules, Ehrlich's triacid; and for 

 mast granules, Jenner. 



1. EhrlicWs Triacid (vide p. 408). Fix with heat 

 (p. 20). Without shaking the bottle pipette off enough 

 to cover the blood film. Stain for five minutes. Wash 

 in water. The neutrophil granules (e) are reddish 

 violet ; the eosinophil (a) are coppery red ; the red cells, 

 orange ; the mast granules and basophilia of the red cell 

 are not shown. The stain is best made by one's self. 



2. Eosin and Methylene Blue. Fix with heat, 

 stain with eosin (p. 408) three minutes. Wash (and 

 dry). Stain with methylene blue (p. 408) two parts and 

 eosin one part, freshly mixed, for half a minute. Wash. 

 Dry. 



3. Eosin and baematein. Fix the film. Stain 

 with eosin three minutes. Wash, stain with haematein 

 (p. 408) half to one minute. Haematein is especially 

 good for studying the differences in the nuclei. 



4. Jennets Stain is the precipitate resulting 

 from the action of a watery solution of eosin on a watery 

 solution of pure unripened methylene blue ; dissolved 

 in methyl alcohol (Tabloid 0*05 gramme; methyl alcohol 

 10 c.c.). 



To stain. Fixing is unnecessary. Place solution 

 on film, covering so as to avoid evaporation. Stain 

 two to three minutes. Add about twice as much H 2 O 

 to the slide. Mix. Stain [five to ten minutes. 

 Especially adapted for the mast granules. 



