The standard procedure of the application of Bouin’s solution on the inked specimen includes the use of a cotton applicator or a pipette. The applicator takes time and sometimes leaves cotton threads. The pipette pours the solution indiscriminately; yellow stain is everywhere, as well as the smell of acetic acid.
If there were a big inked surface, an option would be to use a sponge soaked with Bouin’s solution. I use a Moist Plus Mouth Moisturizer (Sage Industries Inc.) sponge. It has an appropriate size of the foam (25×15 mm). The sponge has a convenient handle. For smaller surfaces or precise applications, I cut part of the foam to create a tip.
There is a different approach to the application of Bouin’s solution on the inked specimen. A horse is brought to a bag of oats. This method is developed predominately for biopsies, skin excisions and small specimens. There are some variants of this method (see “Innovations in Pathology; The Best Of Thirty Years” Chapter 7 “Anatomic Pathology” www.cap.org ).
I use a urethane foam sponge placed in a standard glass slide box. The foam is soaked with Bouin’s solution. For instance, the ink is applied to the skin. The specimen is pressed into the foam creating a soft temporary indentation that surrounds only the skin’s inked part. The specimen can be left on the surface of the sponge for some time. The lid covers the box after the work is done.
This method is efficient, fast, and environmentally friendly. There could be different sizes of boxes and fragments of sponges. There is plenty of this material in a laboratory.
If in a large specimen, mastectomy for instance, the use of a pipette is reasonable, in a case of skin excision an employment of a sponge is more efficient.