Crossword-Solution: PICRO 5 letters, 2 clues 🏆 scrabble score: 9

The best known example is the staining of muscle with picro-carmine, by which the muscle substance appears pure yellow, the nuclei pure red.

Connective tissue and bone substance, however, behave differently with the picro-carmine mixture, in as much as here the diffuse stain depends exclusively on the concentration of the carmine, and is quite uninfluenced by the addition of a chemical antidote.

Bouin’s picro-formol solution consists of:-- Saturated aqueous solution of picric acid 30 volumes Formalin, 40 per cent.

When puered and drenched sheep skin is treated for 20 minutes with a very dilute solution of H_{2}SO_{4} (1/280), it swells up considerably and becomes soft and semi-transparent, The fibres of the skin, which under normal conditions have a diameter of 4µ–6µ become 20µ or more; on staining with picro-carmin there are seen to be certain fibres which are unaffected or only slightly affected by the acid.

Carmine and picric acid may also be combined in one stain, as picro-carmine, but this is rarely used at the present.