312 MEDICAL BACTERIOLOGY 



egg albumin. When the sections are once fixed to the cover the 

 staining can be carried on in the forceps as with ordinary cover- 

 glass preparations. Before staining, however, the paraffin must be 

 removed; this is done with xylene, and this in turn with absolute 

 alcohol. 



References. A. 182 ; M. & W. 204-239 ; N. 531. 



exercise 99. staining sections. 



General Histological Method. 



Hematoxylin and Eosin. 



a. Transfer sections from alcohol to distilled water. 

 &. Stain in alum-hematoxylin 5 minutes. The stain may be 

 prepared as follows (Boehmer) : 



1. Hematoxylin crystals, - 1 gram. 

 Absolute alcohol, 10 cc. 



2. Alum, 20 grams. 

 Distilled water, 200 cc. 



Cover the solutions and allow them to stand over night. The 

 next day mix them and allow the mixture to stand for one week in a 

 wide-mouthed bottle lightly plugged with cotton. Then filter into a 

 bottle provided with a good cork. The solution is now ready for 

 use, but its staining powers improve with age. 



c. Acid alcohol 5 to 10 seconds. 



d. Ammonia water (1%%) until sections are a light blue. 



e. Wash in water. 



/. Counter-stain with eosin (y^-j to %% in 60% alcohol) 3 min- 

 utes. 



g. Alcohol, 95%, two or three changes to dehydrate and remove 

 excess of counter-stain. 



Ji. Clear in oil of origanum, or in Dunham's mixture (white oil 

 of thyme 4 parts, oil of cloves 1 part). 



i. Balsam. 



General Bacteriological Methods. 

 A. Loeffler's Universal Method. 



a. Take sections out of alcohol and place in Loeffler's methylen 



blue for 5 to 30 minutes. 



b. Decolorize in acetic acid (0. 1%) 10 to 20 seconds. 



c. Dehydrate in absolute alcohol, two or three changes, a few 



seconds. 



d. Clear in xylene. 



