210 THE EXAMINATION OF MATERIAL 



(a) Laveran's method. Method recommended. 1. Flood the film with 

 an aqueous solution of eosin (p. 207). Stain for about a minute. 



2. Replace the eosin with a saturated aqueous solution of methylene blue 

 and stain for about 30 seconds. 



3. Wash in distilled water. 



4. Dry and mount in balsam. 



The red cells are stained pink while the bacteria and the nuclei of the 

 white cells are blue. In the blood of birds the nuclei of the red cells are 

 also stained blue. 



(ft) Chenzinsky's method. 1. Lay the cover-glass, film side downwards, 

 in a small ground-glass covered glass dish containing a little of the following 

 solution which must have been recently prepared : 



Saturated aqueous solution of methylene blue, - - 40 c.c. 



0'5 per cent, solution of water-soluble eosin in 70 per cent. 



alcohol, - 20 



Distilled water, - - 40 



Leave the film to stain in the glass dish in the warm incubator at 37 C. for 

 3-6 hours. 



2. Then wash the film in distilled water, dry, and mount in balsam. 



(y) Romanowsky's method. 1. After drying and fixing in the flame, 

 place the film in a drying oven at 105-110 C. for about an hour. 



2. Then immerse the cover-glass in the following staining solution which 

 must be newly made up and not filtered : 



Saturated aqueous solution of Hochst's medicinal methy- 

 lene blue, - 2 parts. 

 1 per cent, aqueous solution of eosin A.G. (Hochst), - 5 



Stain for 2-10 hours. 



3. Wash in distilled water. 



4. Dry, and mount in balsam. 



2. Films of pus, etc. 

 (a) Ktihne's method. 1. Stain for a few minutes with carbol-blue (p. 138). 



2. Wash in water. 



3. Wash in dilute hydrochloric acid until the film assumes a pale blue 

 colour (this is rather a delicate proceeding and the time required will vary 

 with the thickness of the film). 



Dilute hydrochloric acid. 



Pure hydrochloric acid, - 1 c.c. 



Distilled water, - - 1000 



4. Remove the excess of acid by washing in an alkaline lithia solution. 



Saturated aqueous solution of carbonate of lithia, - - 5 c.c. 



Distilled water, - 100 



5. Wash well in water. 



6. Dry, clear in clove oil and xylol, and mount in balsam. The ground- 

 work is stained pale blue and the micro-organisms deep blue. 



(ft) Nicolle's method. Method recommended. 1. Stain for a few minutes 

 in carbol-blue. 



2. Wash in water. 



3. Treat for 2 or 3 seconds with a few drops of the following solution : 



Pure tannin, - ... . 10 grams. 



Distilled water, - 100 



4. Wash in water. 



5. Treat rapidly with absolute alcohol, clove oil and xylol, and mount 

 in balsam. 



