LAURA: Little articles of [glass], they’re ornaments mostly! Most of them are little animals made out of glass, the tiniest little animals in the world. Mother calls them a glass menagerie! Here’s an example of one, if you’d like to see it! . . . Oh, be careful—if you breathe, it breaks! . . . You see how the light shines through him?
JIM: It sure does shine!
LAURA: I shouldn’t be partial, but he is my favorite one.
JIM: What kind of a thing is this one supposed to be?
LAURA: Haven’t you noticed the single horn on his forehead?
JIM: A unicorn, huh? —aren’t they extinct in the modern world?
LAURA: I know!
JIM: Poor little fellow, he must feel sort of lonesome.

This exchange occurs in Scene Seven, after Jim’s warmth has enabled Laura to overcome her shyness in his presence and introduce him to the collection of glass animals that is her most prized possession. By this point in the play, we are well aware that the glass menagerie is a symbol for Laura herself. Here, she warns him about the ease with which the glass figurines might be broken and shows him the wonderful visions produced when they are held up to the right sort of light. In doing so, she is essentially describing herself: exquisitely delicate but glowing under the right circumstances.

The glass unicorn, Laura’s favorite figurine, symbolizes her even more specifically. The unicorn is different from ordinary horses, just as Laura is different from other people. In fact, the unicorn is so unusual a creature that Jim at first has trouble recognizing it. Unicorns are “extinct in the modern world,” and similarly, Laura is ill-adapted for survival in the world in which she lives. The loneliness that Jim identifies in the lone unicorn is the same loneliness to which Laura has resigned herself and from which Jim has the potential to save her.