The only thing I can say is that Picric acid left in tissue ultimately
affects the staining of the nuclei if not neutralized with EtOH
saturated w/ Li2CO3. There is a much better fixative of testes
'Modified Davidson's Fluid'. The pathologist I worked with, Dr Diane
Creasy, published her findings in TOXICOLOGIC PATHOLOGY vol. 30, no 4,
pp524-533, 2002, entitled _Fixation of Testes and Eyes Using a Modified
Davidson's Fluid: Comparison with Bouin's Fluid and Conventional
Davidson's Fluid._ This article describes the recipe for mDavidson's
and compares it to other Fixatives routinely used.
Best of Luck!