grastan chruti-ganan yatha
catuh-yuga-ante-at the end of every four yugas (Satya, Dvapara, Treta and Kali); kalena-in due course of time; grastan-lost; sruti-ganan-the Vedic instruction; yatha-as; tapasa-by austerity; rsayah-great saintly persons; apasyan-by seeing misuse; yatah-wherefrom; dharmah-occupational duties; sanatanah-eternal.