[79] And moreover, venerable sir, this is unsurpassable: the way the Blessed One teaches the Dhamma concerning the attainments of vision (dassanasamāpatti). Venerable sir, there are these four attainments of vision.
Here, venerable sir, some ascetic or brahmin — by dint of ardor (ātappa), by dint of striving, by dint of application, by dint of diligence, by dint of right attention — touches such a concentration of mind (cetosamādhi) that, with the mind (citta) thus concentrated, he reviews this very body, upward from the soles of the feet, downward from the tips of the hair, bounded by skin, as full of impurity of various kinds: 'There are in this body head hairs, body hairs, nails, teeth, skin, flesh, sinews, bones, bone marrow, kidneys, heart, liver, pleura, spleen, lungs, intestines, mesentery, stomach contents, feces, bile, phlegm, pus, blood, sweat, fat, tears, grease, saliva, snot, synovial fluid, urine.' This is the first attainment of vision.
Again, further, venerable sir, here some ascetic or brahmin — by dint of ardor … — touches such a concentration of mind that, with the mind thus concentrated, he reviews this very body, upward from the soles of the feet, downward from the tips of the hair, bounded by skin, as full of impurity of various kinds: 'There are in this body head hairs, body hairs, … synovial fluid, urine.' And going beyond a person's skin, flesh, and blood, he reviews the bones. This is the second attainment of vision.
Again, further, venerable sir, here some ascetic or brahmin — by dint of ardor … — touches such a concentration of mind that, with the mind thus concentrated, he reviews this very body, upward from the soles of the feet, downward from the tips of the hair, bounded by skin, as full of impurity of various kinds: 'There are in this body head hairs, body hairs, … synovial fluid, urine.' And going beyond a person's skin, flesh, and blood, he reviews the bones; and he understands a person's stream of consciousness (viññāṇasota), unbroken on both sides, as established both in this world and in the next world. This is the third attainment of vision.
Again, further, venerable sir, here some ascetic or brahmin — by dint of ardor … synovial fluid, urine. And going beyond a person's skin, flesh, and blood, he reviews the bones; and he understands a person's stream of consciousness, unbroken on both sides, as established neither in this world nor in the next world. This is the fourth attainment of vision.
This, venerable sir, is unsurpassable concerning the attainments of vision.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.