56 MANUAL OF BACTERIOLOGY. 



(c) Wash in distilled water till the thin parts of the 

 preparation have a yellowish or pinkish tint, which requires 

 one to three minutes. 



(d) Dry with blotting-paper and mount in Canada bal- 

 sam. 



Bacteria, malarial parasites, and cell-nuclei are stained 

 blue, red blood-corpuscles are orange-pink, while the specific 

 granules of the leucocytes (neutrophilic, etc.) appear in 

 various tints from red to dark blue. The chromatin of the 

 malarial parasite takes a lilac to red color. The blood-plates 

 have a bluish or purplish color and must not be confused 

 with malarial parasites. 



The staining fluid is prepared as follows : To 100 c.c. of a one per 

 cent, solution of sodium bicarbonate in water add i gram of methyl ene- 

 blue. Place in the steam sterilizer at iooC. for one hour. When cool 

 add one-tenth per cent, watery solution of eosin (Griibler, yellowish, 

 soluble in water) until the mixture loses its blue color, becomes pur- 

 ple, and a metallic scum forms on the surface. About 500 c.c. of the 

 eosin solution are needed. Collect the precipitate on a filter ; let it dry ; 

 make a saturated solution of the precipitate in methyl alcohol; filter. 

 To the quantity obtained add one-fourth as much methyl alcohol, so 

 that the solution may not be completely saturated. The purpose of the 

 above procedures is to modify the methylene-bluc so that other stain- 

 ing elements are developed in it (polychromism). The modified 

 methylene-blue solution is then combined with eosin. For full details 

 see Wright, Journal of Medical Research, Vol. VII. 1902. 



Staining of Spores. The method is applicable to cover- 

 glass preparations which may be prepared in the usual 

 way from material supposed to contain spores. 



(a) After drying the smear on the cover-glass, and fixa- 

 tion with heat by passing through the flame three times, 

 use as a stain aniline-water fuchsin. 



(b) Heat until the preparation begins to boil; remove 

 for a minute; heat again, and again remove; repeat this 

 process six times. 



(c) Wash in 3 per cent, hydrochloric acid alcohol one 

 minute, or less. 



