STAINING, PRACTICAL AND THEORETICAL 



pancreas: not clearly defined. Mitotic figures exhibit conspicuous 

 metachromatic staining. 



Note: The picture is improved if a green filter is used with 

 the microscope lamp. 



Notes: 



{a) In the original paper, which also deals with the pontacyl 

 blue black-luxol fast yellow technique, the authors remark that 

 it is rather surprising that pontacyl blue black SX, which was 

 used by Lillie (1945) as a stain for collagen has now been found 

 to be a good nuclear stain, in simple aqueous solution, without a 

 mordant. 



{b) Both pontacyl blue black SX and pontacyl violet 6R are 

 acid stains, but the first has one amino group and can, therefore, 

 be regarded as amphoteric, whereas pontacyl violet is wholly 

 acid. It is possible that here these two dyes are acting as hydrogen 

 ion indicators. The addition of a suitable mordant to the aqueous 

 solutions of either of these dyes reduces the staining time very 

 considerably. 



{c) The advantages of luxol fast yellow TN as a counterstain 

 are mentioned on page 382, note {b). 



Reference: Wood, M. L. & Green, J, A. (1958a)- 



PX STAIN 

 For keratin, vaginal smears, etc. 



Technique: 



1. Fix smears while still wet in a mixture consisting of equal 

 parts absolute alcohol and ether, for two minutes. 



2. Rinse in 70% alcohol. 



3. Rinse in 50% alcohol. 



4. Rinse in water. 



5. Immerse in the staining solution for three minutes. 



6. Immerse in dioxane for a few seconds. 



7. Wash with absolute alcohol rapidly. 



8. Rinse well in xylol and mount. 



384 



