OF THE ALIMENTARY TRACT 35 



of absolute alcohol, to each 100 cc. of which mix- 

 ture is added 5 cc. of glacial acetic acid) for 10-30 

 minutes. 



2. Rinse in 50^/c alcohol. 



3. Remove the remainder of the corrosive sub- 

 limate by placing in a weak alcoholic solution of 

 iodine for about 15 minutes. 



4. Pass through alcohols, 70%, 80%, and 90%, 

 and wash in distilled water. 



5. Mordant in 4% iron-ammonia-alum over- 

 night. 



6. Rinse in distilled water and from weak to strong 

 grades of alcohol. 



7. Stain in 1% alcoholic haematoxylon until the 

 films are well blackened. 



8. Rinse the excess of stain in water and differ- 

 entiate in 2% iron-ammonia-alum. This is the step 

 requiring most skill and attention. It can be mas- 

 tered only by experience. 



9. When decolorized to the correct point, usually 

 just beyond the point w^hen the color comes from the 

 film into the differentiating fluid as the slide is dipped 

 up and down, rinse in tap water, pass through 

 graded alcohols and into carbol-xylol (or similar 

 clearing agent), xylol, and mount in balsam. 



Do not allow the film to dry at any stage. 



This staining procedure is not easy and many poor 

 specimens to each good one will be obtained, par- 

 ticularly until the technique is mastered and is being 

 fairly constantly practiced. 



