Eight adults sat crammed together across the back of the bus from Dodoma in a seat made to hold four. Two of the women cradled sick babies against their breasts.

The aisle overflowed with baskets and people. Everytime the bus hit a pothole, which was often, three or four people fell to the floor, and the loose chickens under the seats squawked.

Dust rolled in through the windows, covering everyone with a layer of grit. At 10:30 a.m., the temperature hit 95 degrees. It kept rising. During the next nine hours the bus broke down four times.

Yet no one complained. The trip from Dodoma is seldom any different. People accept all this as a matter of course. It is simply one of the realities of life in the Third World.

For the modestly affluent as well as the poor, the difference between life in America and such developing countries as Indonesia, Tanzania and Pakistan can only be described as mind-numbing.

Start with basic transportation.

Buses are universally overcrowded. From Guatemala to Indonesia, drivers stuff four riders into seats designed to hold two. In Cairo, buses cruise through traffic looking likebombarded battleships about to sink. They have permanent lists from carrying too many people.

Trains often look more fit for cattle than humans. Railway stations resemble the impromptu refugee camps they frequently are, with hundreds of people camping out on their floors.

Homes, at times within sight of modern skyscrapers, are often little more than mud huts or lean-tos the size of a refrigerator carton. Raw sewage flows past in open trenches.

Electricity hasn't made it to hundreds of villages. Pure water is a rarity. Sewage systems are almost unheard of. Children in rural schools often don't have books.

Even in the most modern Third World cities, brownouts are a daily occurrence. The public water systems close down for hours at a time.

Rural roads are little more than gravel paths in many countries. City streets are often narrow, ill-kept lanes, crowded with bicycles, pedestrians, motor scooters, horse cars - and sometimes even camels.

Despites everything I had heard or read about the Third World, I was constantly amazed by the contrasts and inconsistencies. There is great wealth as well as great poverty, vast unspoiled wilderness and plains along with smelly, crowded slums.

The 15th and 20th centuries co-exist almost side by side.

One morning while I was having breakfast in Tanzania, an old man with a thick layer of dust caked to his body wandered into the courtyard of my hotel. He wore only a loin cloth around his slender, aging hips. He carried four crudely fashioned arrows and a hunting bow that looked like something out of a Stone Age exhibit at the Smithsonian. He was trying to sell to get money.

That night, a rock band appeared at the same hotel. The music, the dress, the dances and the booze were very Western. Except for the Swahili spoken, I could just as well have been in New York or Chicago.

The American traveler never feels too far from his culture in the Third World. I met dozens of Pakistanis, Tanzanians and Indonesians who had studied and traveled widely in the United States, and who read Time magazine each week.

In Dar es Salaam, the capital of a socialist country, the U.S. Information Service library is filled every night with young people studying Western management training books.

In the ancient Indonesian city of Jogjakarta, I was awakened at 6 one morning by a strange sound blasting out of a speaker across from my hotel. It was a recording by the Kentucky coal miner's daughter, Loretta Lynn.

In some ways, poverty is the same everywhere. One finds the same wretched smells, rats, broken bottles, and hopelessness in the slums of Pakistan that one finds in Washington, D.C.

A child with rotten teeth and a bloated stomach looks pretty much the same in Mississippi as in Indonesia. The maize tortillas Mayan Indians make in Guatemala taste surprisingly like Appalachian cornbread.

The striking thing about Third World poverty is its totality. The poor aren't just a forgotten minority tucked away in public housing projects; they're the overwhelming majority. Almost everyone is poor.

Despite their majority standing, the Third World poor are often treated like animals.

Yet the poor seem to accept their lot as an unchangeable fact of life - something they're powerless to do anything about.

Growing up in poverty, often under totalitarian governments, they learn an acute sense of place at an early age. They know what is accepted and what is not. They seem to develop an incredible tolerance for inconvenience and official arrogance.

A Tanzanian tells of riding all day on a crowded bus from Arusha in the northern part of the country. At nightfall, the driver mysteriously stopped the bus and walked into the woods.

One hour passed, two hours, three hours. The driver didn't reappear until morning. He then started the bus up, and the trip resumed. Never was there a word of explanation on where he'd been, nor a whisper of complaint from any of the riders stranded all night.

The Third World Poor are also very much at the memory of the elements. In the United States, we've built a substructure beneath our poor. They have access to welfare programs, food, stamps, public housing and free school lunches. They are guaranteed a certain minimum standard. It isn't high, but it makes them rich by the developing world's standards.

The only security system available to most of the Third World's poor is their children. There is no Social Security. No welfare. No food stamps. So they put their kids to work at an age when American children are entering first grade.

They need every coin their children can bring home since the basic necessities of life are surprisingly expensive.

A Mayan Indian in Guatemala with $65 annual income, for example, pays almost as much for firewood - $8 for a small stack - as a $35,000 bureaucrat in Washington.

The bureaucracies in most developing countries make the U.S. federal government seem lean by comparison. Though much of the Third World, government is the biggest game in town. And the game is overloaded with players, petty regulations and bureaucratic protocol. Seldom is one person given a job when five or six could do it as well.

In many countries, petty corruption and profiteering are commonplace in the highest ranks of the government and military. Businessmen complain of having to bribe officials for permits and licenses. Workers complain that supervisors in state-run industries pad their salaries with lavish expense accounts, company cars and even levies on employees.

The poor in no way find themselves exempt from paying bribes by virtue of their poverty. Bribes and illegal levies often must be paid to get even the most basic services.

A Tanzanian newspaper reports that bribes are commonly demanded by clerks in government offices before they'll sort through files; by lab technicians before they'll fill in medical forms; by doctors before they'll write out prescriptions; by machinery dealers before they'll sell tractors to farmers.

In some instances, the Tanzanian Daily News said, "A public officer will not fulfill his duties unless the client offers sexual pleasure in return . . . Some male officers will not serve a girl without first having carnal relations with her."

Not surprisingly, in view of this, governments are often hidebound, self-protecting and repressive.

The military keeps a high and threatening profile.

Almost every day during my two weeks in Pakistan, the military government rounded up some alleged opponent of the state and threw him in jail. One day it announced it had decided to ban all public meetings until "sanity" was restored to the country.

Another day, it announced it was postponing elections indefinitely until "positive" results could be assured. Yet another, a rapist was flogged for an hour before a crowd of 10,000 in Rawalpindi.

Tanks patrolled the downtown streets of Jakarta during my stay trying to discourage student protest.

Six weeks earlier, the Indonesian military had closed down seven of the country's biggest newspapers, which at the time were mango the Freestin Southeast Asia.

"We are back publishing, but it's like coming back from a sex change operation," an Indonesian editor said. "There is a big gap between what our readers expect of us and what we can do."

Guatemala was even more disturbing. During one 10-hour day, my car was stopped and searched seven times by machine gun-toting soldiers. My guide, a young American, told of a wave of violence with scores of mysterious murders and kidnappings when he lived in the small highland village of Nebaj during 1976 and 1977.

He personally claimed to have known nine men who had disappeared or been killed, including a Protestant minister and a worker in a Catholic development project.

"Violence has been institutionalized here," one diplomat based in Guatemala City said. "It's an accepted mode of political expression."

A few nights later, I picked up a slender hitchhiker on the narrow road to the grimy port of San Jose. It was 8 p.m. and pitch black outside. The 16-year-old said he's been walking since 3 that afternoon.

Army officers had snatched him off the streets of San Jose the previous day, he said, because he didn't have any identification papers on him. (That is a favorite way of recruiting Indians, who make up the bulk of the Guatemalan Army.) He was taken to the regional capitol of Escuinta 35 miles away for processing into the Army without being allowed to notify anyone.

After keeping him a day, however, the Army decided it didn't want him. "I told them I was my mother's only child," he said. "Besides, I didn't meet the height requirements."

Understandably, such tactics create a deep fear and cynicism among ordinary citizens toward their government.

Life is often a daily ordeal even for professional classes. Dozens of things which even the most lowly paid American takes for granted don't exist - or exist only for elite few.

Basic consumer items are scarce, particularly in countries like Tanzania, which have made concerted efforts to cut down imports. Toilets paper, for instance, all but disappeared from shops in the northern part of the country during the early months of 1978.

A Volkswagen bus which sells for $6,500 in the United States costs $13,000 in Tanzania, where members of the president's cabinet are paid less than $7,000 a year.

Even for those few with amply incomes, there are still difficulties.

In many places, it's almost impossible to get a telephone unless you're born to it, or happen to move into a house that already has one. One Australian told me he spent $1,400 to have a phone installed in his Indonesian home.

"I have a phone and number in the book," said an Englishman in Bogor, Indonesia. "But they tell me it will cost 170,000 rupiahs (about $400) to connect them."

Getting it hooked up, moreover, is no guarantee that it will work.

Phones are maddeningly undependable. One call can occupy an entire morning. At an airport hotel in Cairo, I told the desk clerk that I needed to telephone a colleague on the other side of the city.

"That'll take four hours to get through anyway," he said with a laugh.

Even a simple journey often becomes an obstacle course.

The trip I took from Dar es Salaam to Dodoma, an inland city of 45,000 about 200 miles away, is a case in point.

The cities are connected by a railroad, a rough gravel highway and four airline flights a week. But for some reason - and it isn't for lack of passengers - the state-run airline ends up cancelling at least one of its weekly flights. This fouls up the whole transportation system, making train and plane reservations impossible.

After a week of trying, I got a spot on the night train through a Tanzanian friend who knew the assistant railway station manager.

The train was one of the reminders that pop up everywhere of East Africa's colonial past. The Germans built it before World War I. It must have been a grand sight in those days, with its wood-paneled coaches and porters in starched white jackets.

Today, it is filthy, overcrowded and in severe decay. A layer of dirt and perspiration stains coats everything. By 11 p.m. on an overnight trip, half the toilets in the train aren't functioning and shabbily clad peasants are asleep shoulder-to-shoulder in the hallways.

The stench of fresh urine and sweat permeates the air. The tropical heat is impossible. It engulfs and smothers you. And every time the train pulls to a stop at another village of mud huts, a few more peasants clamber aboard through the open windows.

Five of us with seven suitcases, two cardboard boxes and a big basket of bread were assigned to the same closet-sized second class compartment. I'd been told to buy my ticket on board, and was informed the fare would be 46 shillings.

When the conductor came, I complained about the crowded conditions and gave him a 100-shilling note (worth about $12). He said he didn't have any change. I took that to mean the extra money would help me get a better spot on board. It eventually did. Two hours later I was reassigned to another dirty compartment with one other man.

A young doctor in a dining car was outraged about the condition of the train and the general inefficiency of the country. A loud man heavy with whiskey on his breath sat down beside him. When he noticed nobody in the car had been given glasses for his beer, he began barking authoritatively. Soon, glasses appeared.

The doctor, seeing that the drunk appeared to be a man of some influence, immediately began complaining. Why was the train so filthy?Why was the food so bad? Why was the beer so warm and the soup cold? And why did everyone put up with such a mess?

"What do you want," the man answered solemnly. "Are you too good for us common people? Do you want to ride in the airplane with all the fancy people? You want comfort. You want luxury all around you."

"I don't see anything wrong with a few luxuries," the doctor said.

The man replied: "There are no luxuries in this country."