In this lesson Still Hungry, we learn of four things which are never satisfied. The leech is the symbol of an insatiable appetite because it sucks blood through its two suckers (here called its “two daughters” who cry “Give, give!”).  It is found in stagnant waters everywhere. Proverbs 30:15-16  The horseleach hath two daughters, crying, Give, give. There are three things that are never satisfied, yea, four things say not, It is enough: The grave; and the barren womb; the earth that is not filled with water; and the fire that saith not, It is enough.