I walked quickly through the kids playing in front of the liquor store at the corner, looking among them for my Little Sister.

I could hear the noisy arguments from the billiard room and bar next door as I knocked on the door of the ground-floor apartment where she lived. Maritza's Mama let me in. "Your Big Sister's here, Maritza."

"I'm sorry for not coming last week. I was sick," I announced to the small, dark room where eight-year-old Maritza sat basking in the irregular glow of the television set. Guilt strangled me, because I knew I could, and should, have gone.

I asked Maritza about her homework, and after much prodding she pulled her bag from under the sofa. She showed me a crumpled assignment sheet with rows of addition and subtraction exercises.

As we worked through the problems, I realized she was not up to the average level of mathematical expertise I expected of a third-grader.

Finally she seemed to understand what she needed to do, and she began slowly scribbling the answers on the tired-looking paper, while her four-year-old brother weaved his Matchbox car in and out between our legs. The television blasted the soundtrack of a black-and-white Spanish movie that her stepfather was watching, and I tried to stifle my unruly thoughts.

Maritza was fidgety, withdrawn and reticent as usual, and we didn't accomplish much. Her Mama screamed admonitions from the kitchen, telling her she'd better not think about dropping out, as her 12-year-old sister did once.

Tu sabes what it's like to have a child at 15 and then, 12 years later, despues de todo lo que has hecho, have her drop out? Her Big Sister didn't do nothing--do you know her, Evelyn or something? Gracias a Dios Nana got bored and went back, but she flunked...So Maritza, you better do what your Big Sister tells you, you hear?"

I wanted to hide from the stifling hopelessness that permeated the house, to cry for the menial, wasted lives of so many people trapped in their own inadequacy. I wanted to escape the cloud of despondency that dazed my mind and numbed my spirit.

Most of all, I wanted to avoid my own sense of helplessness and frustration. But I had a responsibility to carry out, so I did my duty, and after dinner I fled, paroled until next week.

Every time I think about Maritza I feel the same sadness and disenchantment, as well as a pervading sense of guilt. I remember walking back to Harvard that evening, overwhelmed by the knowledge I could no longer avoid: I hate myself for not being able to cope with an apathetic eight-year-old to whom I'm supposed to be a good example. I had realized that long before that night, but I didn't want to admit--even to myself--that I had failed as a Big Sister.

WHEN I volunteered to work for the Keylatch Committee of Philips Brooks House, I thought I could make a difference in the lives of those who were less fortunate. In the patronizing manner of those who think they can achieve the impossible, I underestimated the problems of Villa Victoria, a housing development near the Back Bay area that is almost entirely Puerto Rican.

And I overstimated my own abilities to cope in any situation I encountered. I had my doubts, but I refused to back down from the promise I had made to myself. I'll be all right, I thought, it can't be that difficult.

I was wrong.

The first time I went down to Villa Victoria to meet my Little Sister I felt happy and relieved because the neighborhood was not as bad as I had expected. I didn't see any gangs roaming the streets, or any drug pushers aiming automatic weapons at us.

But each time I went down there I felt a reluctant but ever-increasing awareness of the apathy that permeates the life of Villa Victoria residents, and the complacency with which they accept the status quo. Each time I visited the houses of Maritza or her friends and neighbors, I wondered what I was doing there, administering band-aids to people with broken spirits.

I dread going back, because there I come face to face with my shortcomings. In the faces of those children I see a reality my generation won't be able to change, because none of our grandiose plans for making the world better will bring to their eyes the sparkle they never had.

Yet, I can't quit, can't stop trying to help, for that would make me an accomplice to the apathy and complacency that assassinate the human spirit. I haven't found what I'm looking for: a long-term strategy of improvement and repair for our ailing society. Perhaps I never will. But I know now that I'm not satisfied with the standard phrase of comfort frustrated volunteers get: "Anything is better than nothing."