From Hindupedia, the Hindu Encyclopedia
By Swami Harshananda
Puru was a prince of the lunar race held up as an ideal of a devoted son. He was the youngest son of the king Yayāti and Śarmiṣṭhā. Even when Yayāti grew old, his desire for sense-pleasures had not abated. Hence he requested his four sons one by one, to exchange their youth with his old-age. Only Puru, the last son obliged. Yayāti then crowned him as the king and left for the pursuit of pleasures. However, after a long time, Yayāti discovered to his dismay, that desires and especially lust grow in intensity rather than decrease by enjoyment just as fire blazes forth more and more as ghee is poured into it. This story appears in several purāṇas. The one in the Ādiparva of the Mahābhārata is the earliest.
- The Concise Encyclopedia of Hinduism, Swami Harshananda, Ram Krishna Math, Bangalore