STAINS AND STAINING 27 



8. Rinse each slide individually in absolute alcohol until no more color 

 comes away. 



9. Transfer the slides to balsam and mount in the usual manner. 



This is one of the most brilliant of all the triple stains, and a successful 

 preparation shows the nuclei in blue-black and the cartilage in clear blue. 

 Other connective tissues are green, white fibrous connective tissue being light 

 green, and bone is a most brilliant green in contrast to the orange muscle and 

 blue cartilage. Red blood cells are yellow and most nerve tissues are colored 

 a neutral grey. This stain is little more trouble to apply than Mallory's, but 

 the results are both more brilliant and more permanent. 



Many complex stains rely on the fact that a mixture of eosin and methylene 

 blue solutions gives rise to a precipitate which, though insoluble in water, is 

 soluble in methyl alcohol. These stains are used mainly for blood films, not 

 only to differentiate the cell types but also to display the parasites present. 

 The best known of these is: 



Wright's Stain: 

 The preparation of this stain is very complicated. (It is described in Gray's 

 Microtechnique.) It is strongly recommended that the solution be purchased 

 and used as it comes from the bottle. 



METHOD, AS APPLIED TO AIR-DRIED BLOOD SMEARS, IS AS FOLLOWS: 



1. Flood the stain on the slide from a drop bottle and leave for 2 minutes. 



2. From another drop bottle, add distilled water drop by drop until a green 

 scum forms on the surface of the stain. 



3. Wash slide in distilled -water until no further color comes away. 



4. Dry and examine the slide. 



This is the standard stain used for counting and differentiating leukocytes. 

 There are hundreds of variations to this method, and also hundreds of other 

 methods of staining blood. Wright's stain is, however, the basic method from 

 which most others have been derived. 



Complex Botanical Stains 



Most of the combinations used for zoological staining, such as hematoxylin- 

 eosin, can also be used in plant structures, where it is desired to differentiate 

 between the nucleus and the cytoplasm. It is only a matter of convention that 

 the safranin and light green combination, so little used in zoological tech- 

 niques, is preferred by most botanists for their material. 



The complex stains are an altogether different matter, since the chemical 

 nature of plant structures is naturally different from that of animals. The best 

 of these complex botanical stains is: 



