94 The Preparation of Microscope Slides 



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 

 "Microtomist's Formulary and Guide.") 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 min. 



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 leu- 

 kocytes. There are hundreds of variations to this method, and also hun- 

 dreds of other methods of staining blood. Wright's stain is, however, the 

 basic method from which most others have been derived. 



The use of Wright's stain is almost invariably confined to blood smears. 

 Methylene blue-eosin techniques may be applied to sections, usually for 

 the purpose of displaying bacteria in pathological material. The method 

 of Mallory is standard. 



Mallory's Methylene Blue-Azure II-Phloxine: 



First staining solution 



2.5% phloxine 

 Stock second staining solutions 



A. Methylene blue 1 

 Sodium diborate 1 

 Water 100 



B. 1% azure II 



Working second staining solution 



Stock A 5 



Stock B 5 



Water 90 

 Differentiating solution 



95% alcohol 100 



Resin 0.5 



Method of Use 



1. Accumulate slides in distilled water. 



2. Place slides in a coplin jar of first staining solution. Place in oven at 

 55° C for 1 hr. Remove from oven and cool to room temperature. 



3. Rinse briefly in distilled water. 



