Digha Nikaya 2:61
SUJATOPuna caparaṁ, bhikkhave, bhikkhu seyyathāpi passeyya sarīraṁ sivathikāya chaḍḍitaṁ aṭṭhikasaṅkhalikaṁ samaṁsalohitaṁ nhārusambandhaṁ …pe…
Furthermore, suppose they were to see a corpse discarded in a charnel ground, a skeleton with flesh and blood, held together by sinews …