Among the sharp and blunt instruments, alkali is the most important, because it cuts, pierces, and scratches, because it destroys the three doshas, and because it is used for special procedures.
It is not contradictory that even that cool [fire] has the power to burn, cook, cut, etc., because it is mostly composed of the qualities of the fiery herbs. It is pungent, hot, sharp, digestive, liquefacient, purifying, healing, drying, astringent, scraping, destructive of worms, flatulence, phlegm, leprosy, poison, and fat, and when excessively used, it impairs virility.