Fire is conserved in wooden sticks, and when circumstances are favorable, the fire is ignited. But the wooden sticks which are the cause of the fire are also consumed by the fire if it is properly dealt with. Similarly, the living entitys conditional life of material existence is due to his desire to lord it over material nature and due to his envy of the Supreme Lord. Thus his main diseases are that he wants to be one with the Supreme Lord or he wants to become the lord of material nature. The karmis try to utilize the resources of material nature and thus become its lord and enjoy sense gratification, and the jnanis, the salvationists, who have become frustrated in enjoying the material resources, want to become one with the Supreme Personality of Godhead or merge into the impersonal effulgence. These two diseases are due to material contamination. Material contamination can be consumed by devotional service because in devotional service these two diseases, namely the desire to lord it over material nature and the desire to become one with the Supreme Lord, are absent. Therefore the cause of material existence is at once consumed by the careful discharge of devotional service in Krsna consciousness.