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 (l 1 /^) until sections are a light blue. 



e. "Wash in water. 



/. Counter-stain with eosin (-^ to y 2 % in 60% alcohol) 3 min- 

 utes. 



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

 excess of counter-stain. 



h. 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. 

 I. 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. 



