NEW METHOD FOR ORAM STAIN 179 



Inunerse in xylol or turpentine for several minutes or until 

 clear. Examine. 



If the first attempt at staining a smear does not give satisfac- 

 tory results it is advisable to wash off the oil with xylol, wash 

 off the xylol with acetone and restain. It has been our experience 

 that restaining smears gives better results than the original 

 attempt. 



A. The film can be made in either distilled or tap water or 

 physiological salt solution. 



B. Some workers recommend cooling the slide before flooding 

 with the dye. With some dyes steaming seems to improve the 

 result or shorten the required period of exposure. Passing the 

 slide through the flame until steaming Iiegins and allowing to 

 stand the two minutes is sufficient. Steaming does not cause 

 the Gram negative organism to resist decolorization. Anilin- 

 gentian-violet can be used in place of the aqueous solution if 

 desired. .Vllowing the stain to dry around the edge makes a 

 dirty slide but does not affect the Gram reaction. The strength 

 of the solution of the dye and the period of exposure can vary 

 somewhat without affecting the result. A saturated instead of 

 a 5 per cent solution of sodium bicarbonate may be used. 



C. The excess stain can be blotted off or washed off by a 

 brief exposure to water. The exposure to the water should be 

 as brief as possible as water tends to reduce the amount of dye 

 in the cells. Washing with water has the advantage of giving 

 cleaner slides and effecting a saving of the iodine solution and 

 the decolorizer. 



D. The iodine solution can be blotted from the slide but 

 this has the disadvantage of leaving a small amount of iodine 

 on the slide and with the volatilization following the addition of 

 acetone there is some irritation of the exposed mucous mem- 

 brane of the worker. If for any reason one can not complete 

 the staining process after reaching this stage it is advisable to 

 place the slide in water until the staining can be completed. 



E. The decolorizer should be placed upon the slide, allowed to 

 stand for a few seconds and drained off. Then fresh decolorizer 

 allowed to flow over the surface of the slide until it drops off 



