There is a slum in the center of this capital that is divided into three parts. The sections are named Brooklyn, Boston and Cite Simone.

Brooklyn and Boston are names bestowed by local residents who dream of some day going to the United States. Cite Simone is in honor of former dictator Jean-Claude Duvalier`s mother and what was supposed to be a model housing project for the poor.

The slum, home to about 125,000 people, is a place where misery is the way of life; where there is no running water, sewers also serve as bathtubs and swarms of flies alight on arms and faces; where 70 percent of the population are children and 50 percent of the people die before age 5.

It also is the home of Rev. Lawrence Bohnen, a 72-year-old Salesian priest who came here 31 years ago in search of the poorest place he could find and to whom hundreds of thousands in the slum feel they owe their survival.

Lanaud Derazin, 20, who has lived here all his life, told in a combination of his native Creole mixed with broken English and French what the priest means to the slum.

''All the people here like him because he is a very good boy and a very tender president. He makes everything for us here,'' he said.

Rev. Bohnen runs what he calls 140 ''mini schools'' that feed 15,223 children every school day. It is the only food most of them get.

''One day it is corn and beans, the next day it is beans and corn,'' Rev. Bohnen said as a smile crossed his surprisingly youthful face. ''Two million meals a year. It is the biggest diners` club in the world.''

Two other Salesians provide materials for housing and clean drinking water for the people.

A Dutchman, Rev. Bohnen was teaching Greek in Belgium when he decided in 1955 that work among the poor was what he really wanted to do.

''Anybody can teach Greek, as long as you know Greek,'' he said whimsically. ''This is much more interesting.''

To feed thousands of children, the priest and his staff start cooking at midnight. The meals are served in two large feeding centers and several smaller ones that dot the slum from 8 a.m. to 2 p.m..

The cost of educating and feeding a child for a year is $41. ''Not bad, eh?'' Rev. Bohnen asked.

Most of his money comes from private donations from Europe, Canada and the U.S. Each summer the priest criss-crosses America on a Greyhound bus, raising money by speaking in local churches and Salesian communities.

The help Rev. Bohnen and the other priests give the people of the slum is one of the few forms of aid they get. During the 29 years of the Duvalier family regime, first under Francois ''Papa Doc'' Duvalier and later under his son, ''Baby Doc,'' the government provided street signs and a few electricity lines, but nothing else.

''Late last year they paved one road. It took 29 years to pave a road. That is how much they care about poor people,'' Rev. Bohnen said as he walked through Brooklyn.

Hundreds of children milled around as the priest passed from one miserable street to the other, stepping through the mounds of garbage, rotting food and human excrement.

''This is 5th Avenue,'' he said, pointing down a rutted, dirt alley,

''just like in New York.''

The houses on this 5th Avenue are of plywood and cardboard, one-room tin- roofed dwellings. Little girls fill pots from a canal filled with stagnant water that runs down the center of the alley and carry the stinking liquid back into the shacks.

A small boy who wore only a tattered white T-shirt ran up and said,

''Give me one dollar.''

''Don`t,'' Rev. Bohnen said. ''It does not help to just give out money. You have to look for a more permanent solution.''

Larger streets cross open sewers that belch noxious odors. Women squat beside the sewers with baskets offering a few puckered oranges and perhaps an egg or two for sale, their only means of earning a living.

Throughout the tour, the priest showed little sign of emotion. But as he was leaving Brooklyn, he spotted a woman slapping a small boy across the face and neck.

''Stop that, stop that immediately, you stupid woman,'' he screamed, waving his arms in the air and twisting his face in a rage.

On the whole, the priest said, he still is amazed at the cheerful nature of the people in the slum and the lack of crime and violence. Despite the horrible conditions in which they live, the people of Brooklyn, Boston and Cite Simone smile and make friendly conversation with visitors.

After three decades, however, Rev. Bohnen can see no quick solution to the grotesque poverty of Brooklyn, Boston and Cite Simone.

The fall of Duvalier on Feb. 7 has brought some hope that a new government will make it easier for people like Rev. Bohnen and private relief groups to help. However, the poverty of Haiti is so vast that it will take decades to even make a start, the priest said.

Last week, foreign diplomats here said Haiti`s treasury was nearly empty. They estimated the central bank had less than $1 million in foreign reserves and commercial banks had only about $12 million.

The priest`s work in education is part of what many foreign relief workers think is Haiti`s most pressing problem. An estimated 85 percent of the people are illiterate.

''I always say that while I am doing this work, I am doing no other wrong,'' Rev. Bohnen said.

A popular slogan since Duvalier fled is ''every four years,'' a reference to the hope that regular presidential elections will be established.

Driving through the edge of Boston, a teenager spotted that slogan painted on the rear window of the car in which Rev. Bohnen was riding. Smiling, he stuck his head through the open window and said, ''Yes, every four years. Every four years we eat.''

Then, he laughed melodically and waved farewell.