NUEVO Laredo, Mexico, 1977. I am visually assaulted by poor people selling toys, crafts, and food. In order to avoid being mobbed by vendors, I am not, my mother says, to let my curiosity get out of hand in this border town.

But I did, and I recall carrying an awful lot of miniature cap guns out of Mexico at the end of that day. I also remembering the vendors taking American dollars as well as pesos.

I also recall thinking there were few really poor people Nuevo Laredo or Piedras Negras, where we visited the following day. After all, everyone was working, and working hard selling cap pistols or toy tops. How could anyone have been truly down and out?

PORT-AU-PRINCE, Haiti, 1980. My oldest brother was letting off a steady stream of terse French phrases while walking through the Iron Market. He used stock phrases, usually ending up with "Tu n'en as pas besoin" (You don't need it) to a beggar or "Je n'en ai pas besoin" (I don't need it) to a street vendor.

I remember images of abject poverty in this the poorest country in the Western Hemisphere. Thin people leading thinner cows down the roads. Malnourished children eating toasted ears of corn on the sidewalk. And all of this across the street from a presidential palace the size of the Jefferson Memorial.

And I wondered how my brother, a good liberal ideologue, could have hardened himself so drastically.

TRENTON, N.J., 1983. It had been about seven years since we moved into town, and my father's work atmosphere was more depressed and dangerous than ever. He is an Episcopal priest who took the Trenton job because he thought he could make a difference.

I ushered his Sunday services; that is, I stood at the back of the church, handed programs to the people, and explained to people that I wanted to go to Harvard while making sure "undesirables" didn't stagger in.

That year a whole lot of new characters hit the streets. They weren't homeless types, but deinstitutionalized mental patients, freed from county facilities by a new county policy that succeeded wonderfully at freeing Mercer County from fiscal responsibility (i.e., matching funds for Trenton). Many of these people were on the edge of control, their stability dependant on medication.

But there were also addicts, people who would ask you for money to buy coffee and then go out and buy vodka or drugs.

My father tells these people he isn't a bank. My reactions are about the same--except that I also wonder how a man of the cloth could be so hard of heart.

But I recalled the days in Mexico in which you had best not earn a reputation for being free with your money or else they would go after you again and again.

And also, I rationalized, there are dangers in approaching some characters; once a street person took a crowbar to the Madonna statue in the Roman Catholic cathedral across the street.

CAMBRIDGE, Mass., 1987 I walk down Mass. Ave. from Currier House (due to a now totally inadequate shuttle system) and I am accosted by voices:

"Excuse me, sir. Can you spare some money..."