(18) If the staining reaction is excessively alkaline, this can be corrected by
decreasing time of staining or neutralizing the stock stain solution with 1 percent acetic
acid or 1 percent hydrochloric acid. Add the acid a drop at a time. Check the results
after the addition of each drop of acid with trial slides.
(19) If the staining reaction is excessively acid, this may be corrected by
increasing the time of staining or neutralizing the stock stain solution with 1 percent
potassium bicarbonate or a weak solution of ammonia water. Add the ammonia water
or potassium bicarbonate one drop at a time. Check the results on trial slides after the
addition of each drop of the neutralizer.
(20) Staining reactions can also be varied by adjusting the proportions of
disodium phosphate and potassium acid phosphate used in preparing the buffer. For
example, increasing the proportion of disodium phosphate will make the buffer more
alkaline; reducing it will make the buffer more acid.
(21) A poorly stained smear can sometimes be saved by washing rapidly with
95 percent alcohol, washing quickly in water, then restraining.