“Joined together with bones and sinews, having a plastering of skin and flesh, covered with hide, the body is not seen as it really is—full of intestines, full of stomach, of the lump of the liver, of bladder, of heart, of lungs, of kidneys and of spleen, of mucus, of saliva, and of sweat, and of lymph, of blood, of synovial fluid, of bile, and of fat, … and its hollow head is filled with brain. A fool, overwhelmed by ignorance, thinks of it as beautiful, but when it lies dead, swollen up and discoloured, cast away in a cemetery, relatives have no regard for it. Dogs devour it, and jackals, and wolves and worms. Crows and vultures devour it, and whatever other living creatures there are. The bhikkhu possessing knowledge here, having heard the Buddha's word, indeed understands it, for he sees the body as it really is.”

§ 194-202
Pali Canon, Sutta Pitaka, Khuddaka Nikaya (Minor Collection), Sutta Nipata (Suttas falling down)