MICROSCOPIC STUDY AND STAINING 111 



Nicolle advises the use of a ten per cent aqueous solution of tannic 

 acid for a few seconds after washing with the acetic acid. 



Sections may also be stained by placing them over night into a 

 dilute Giemsa solution (one drop to each c.c. of distilled water). When 

 so stained the sections must not be run through the weaker alcohols 

 but must be rapidly differentiated in absolute alcohol. 



METHOD OF STAINING GKAM-POSITIVE BACTERIA IN TISSUE SECTIONS. 

 Celloidin Sections. After fixing section to the slide by pressure with 

 a filter paper or by ether vapor, cover with anilin-water gentian-violet 

 five minutes. 



Pour off excess of stain and cover with Gram's iodin solution for 

 two minutes. Decolorize with ninety-five per cent alcohol until no 

 more color comes out. 



Stain quickly with eosin-alcohol (ninety-five per cent alcohol to 

 which enough eosin has been added to give a transparent pink color: 

 about 1 : 15). Clear in eosin-oiLof origanum (oil of origanum, 25 c.c. 

 and eosin alcohol, as above, about 3 c.c.). Blot and mount in balsam. 



Paraffin Sections. Stain with anilin-water gentian-violet five to ten 

 minutes. 



Wash in water. 



Cover with Gram's iodin solution one minute. 



Wash in water. 



Decolorize with absolute alcohol until no more color comes out. 



Clear in xylol. 



Mount in balsam. 



Gram-Weigert Method. 1 (For celloidin sections.) Stain for one-half 

 hour in the following freshly filtered solution: 



Carmine .* 3-5 grams. 



Saturated aqueous solution of lithium carbonate 100 c.c. 



Dehydrate in ninety-five per cent alcohol. 



Stick section to slide with ether vapor. 



Stain in anilin-water gentian-violet for five to fifteen minutes (or 

 in a saturated solution of aqueous crystal violet diluted with water one 

 to ten, five to fifteen minutes) . 



Wash in physiological salt solution. 



Cover with Gram's iodin solution one to two minutes. 



Wash in water and blot. 



1 Weig&rt, Fortschr. d. Med., v, 1887. 



