In Volume One, Chapter Sixteen of Krishna, the Supreme Personality of Godhead, Srila Prabhupada points out that whereas previously Kaliya was vomiting poison, now his poison was exhausted and he began to vomit blood. Thus he had been cleansed of the vile contamination within his heart that had manifested as serpent's venom. The word smritva, "remembering," is very significant here. The wives of Kaliya were actually serious devotees of Lord Krishna, and according to the acaryas they had often tried to convince their husband to surrender to Him. Finally, finding himself in unbearable agony, Kaliya remembered his wives' advice and took shelter of the Lord. Srila Visvanatha Cakravarti Thakura explains that Kaliya's arch-rival had traditionally been Garuda, the carrier of Vishnu. But now Kaliya realized that he was fighting an opponent who was thousands of times stronger than Garuda and who therefore could be only the Supreme Personality of Godhead. Thus Kaliya took shelter of Lord Krishna.