Some of the women have black-and-white photographs pinned to their sweaters. Others carry mental pictures. None has forgotten her husband or her son. Each is determined to find out whether he is alive or dead.

Some of the women are still able to walk, to knit, to talk quietly among themselves. Sometimes those with enough energy sing to keep their spirits high. Others stare, glassy-eyed, at nothing in particular, whle many more now sleep most of the time, their bodies weakened from lack of food.

As night descends upon the cavernous chapel at the Church of San Juan Bosco, in one of Santiago's drab, working-class neighborhoods, eerie shadows begin to obscure the 24 women who have been on a hunger strike in this church since May 22.

Along the chapel's walls, crypt-like beds many of them containing women wrapped in blankets, give San Juan Bosco the look of a mausoleum.

"We will stay on strike indefinitely, until we get the answer we want," said Monica Gana de Bruce, sitting in her cot among the shadows. "I think my husband is dead. But I want the government to tell me when, how and why."

Alan Roberto Bruce Catalan, identity card number 7,202,425, was a member of Chile's most radical leftist group, the Leftist Revolutionary Movement, according to his wife. After the 1973 military coup that overthrew the leftist government of former president Salvador Allende, Bruce went underground to fight for the armed revolution he believed in. He was caputred on Feb. 13, 1975 and was last seen alive, according to his wife, with an eye torn out, hanging by his arms, about two weeks after his arrest, at in infamous detention center here called Villa Grimaldi.

Bruce is one of 618 persons listed as missing by the Catholic church's official human rights organization in Chile, the Vicariate of Solidarity. As with the others, the Chilean military government has never acknowledged that it arrested Bruce. Although others who survived their time at Villa Grimaldi told Monica Gana they saw her husband there, the government has never admitted detaining him.

Along with 84 other relatives of Chile's missing persons - and 56 supporters, mostly priests and nuns - Monica Gana has refused to eat for 12 days now in a desperate effort to force the government to admit that it arrested her husband and to tell her and the others whether their relatives are alive or dead.

Each day since the strike began, as the relatives of the missing persons and their supporters here lose strength for lack of food, their cause gains strength as more and more of the world takes notice. Telegrams pour in from abroad and groups in several countries, including at least one in the United States, have vowed to fast until the strikers here either get the information they want or lose consciousness trying.

(Lawrence Birns of the Council on Hemispheric Affairs, said in New York that sympathy demonstrations were being held in 56 cities in 20 countries.

(In Washington, five Chileans and four Americans began a sympathy hunger strike at St. Matthews Cathedral. Five Chilean women whose relatives have dissapeared also visited Washington where they met with State Department human rights officer Patricia Derian. Earlier they had met with U.N. Ambassador Andrew Young in New York).

Conversations between the government and the strikers have been going on here for a week in an effort to find a way to end the strike that is acceptables to both sides, Raul Cardinal Silva Henriquez, archbisop of Santiago, has served as mediator.

Late yesterday the government issued a hard-line statement saying it would make no gesture to help persuade the strikers to end the strike.

"The government has been occupied trying to clarify the cases of the missing persons," the statement said, and added that the government "will not make any gesture to end the strike - that is the exclusive responsibility of those who instigated it."

The government's statement was interpreted here as a rejection of a plan put forward Thursday by Cardinal Silva. Although details of the cardinal's solution were not made public, it is believed that he suggested the formation of a commission to investigate each of the 618 cases of involving missing persons. Members of the commission would have been drawn from the government, the church, the families of the missing and other citizens, probably lawyers, trusted by both sides.

It is believed that the striking relatives have demanded that the government first acknowledge that it has secretly arrested and detained - and possibly tortured to death - at least some of those on the church's list.

Apparently, the government, after considering the cardinal's proposal, decided it could not agree to anything requiring it to admit, after 4 1/2 years of denials, that Chile's security police had any part in the disappearances.

It is thought, however, that some segments of the military have argued that the government must acknowledged the missing persons issue if Chile is to continue on its course toward eventual restoration of civilian rule.

El Mercurio, a newspaper that often both reflects and leads government opinion, acknowledged for the first time Sunday that at least some of those listed as missing had been detained by the government, and implied that th government had responsibility for some deaths.

There is a great deal of mistrust on both sides. The military government views the missing persons issue as a political effort by leftists inside the country and abroad to embarrass the junta headed by President Augusto Pinochet, which has attempted to rid the country of both the leftists who supported Allende and the ideas that they espouse.

For their part, the relatives of the missing people believe the military government for years has rebuffed their efforts to find out whether their sons and husbands are alive or dead. The relatives charge that a political amnesty announced by the government last April was really designed to absolve any security policemen from prosecution for crimes they may have committed after the coup.

Homicide is specifically included in the amnesty as one of the crimes that is pardoned and courts here have been throwing out habeas corpus cases filed by relatives of the missing persons on the grounds that any crimes committed against those listed as missing have now been forgiven.