Taste, smell and sharpness

Meaning

Taste, smell, biting, and sharpness describe the changed subject after the preliminary work. They mark a contrast with the original heavy and rough condition. Crucially, the same passage says that this apparently delightful material remains more a harmful poison than a useful medicine without further preparation. Agreeable sensory description therefore provides no assurance of safety. The historical mention of the tongue is recorded as part of the author's description, not repeated as an instruction to taste unknown substances.