Treatment of superficial vein reflux (see Varicose Veins, above) has been shown to decrease the recurrence rate of venous ulcers. Where there is substantial obstruction of the femoral or popliteal deep venous system, superficial varicosities supply the venous return and should not be removed.

The infrastructure of Amsterdam all depends on a stone at the center of Dam Square. The stone caps a bolt that marks Amsterdam’s zero-level, or sea level, based on high tide in the summer of nearby Zuiderzee Bay. The reference point, called Amsterdam Ordnance Datum (which translates to Normaal Amsterdams Peil, or NAP), is the heart of the European network of national leveling networks. In other words, the NAP is the prime meridian of elevation. 

Narratives of the lives of Jesus, Buddha, Mother Teresa, and other inspiring figures are full of stories of people who, upon meeting the saintly figure, dropped their former materialistic pursuits and devoted themselves to advancing the mission of the one who elevated them. Indeed, a hallmark of elevation is that, like disgust, it is contagious.

In both studies, reported feelings of happiness energized people to engage in private or self-interested pursuits, while feelings of elevation seemed to open people up and turn their atten­tion outwards, toward other people.

Social disgust can then be understood as the emotional reaction people have to witness­ing others moving “down,” or exhibiting their lower, baser, less God-like nature. Human beings feel revolted by moral depravity, and this revulsion is akin to the revulsion they feel toward rotten food and cockroaches. In this way, dis­gust helps us form groups, reject devi­ants, and build a moral community. I thought about the social nature of dis­gust in this way for years, and about what exactly it means when someone moves “down” on the vertical dimension from good to evil.

. Psychologists have thought about morality primarily as a system of rules that prevents people from hurting each other and taking their possessions. But I believe that morality is much richer and more balanced. Most people don’t want to rape, steal, and kill. What they really want is to live in a moral community where people treat each other well, and in which they can satisfy their needs for love, productive work, and a sense of belonging to groups of which they are proud. We get a visceral sense that we do not live in such a moral world when we see people behave in petty, cruel, or selfish ways. But when we see a stranger perform a simple act of kindness for another stranger, it gives us a thrilling sense that maybe we do live in such a world.

Here’s a puzzle: why do we care when a stranger does a good deed for another stranger? Most theories in the social sciences say that people’s actions and feelings are motivated by self-interest. So why are we sometimes moved to tears by the good deeds or heroic actions of others?

A second line of research is about "elevation," which refers to the warm, uplifting feeling we get when we witness someone else's good deed. Research by moral psychologist Jonathan Haidt, as well as by Simone Schnall, has found that elevation systematically motivates people to perform altruistic acts themselves.