“Midnight shakes the memory
As a madman shakes a dead geranium.”
Eliot borrowed the geranium, along with the lunar imagery, from the French symbolist poet Jules Laforgue.
In this simile, he relates what the night is doing to his memory—“shaking” it, disorienting it—to a madman shaking a “dead geranium.” He is describing lunacy, or temporary insanity brought on by changes in the moon. The absurd image of a lunatic shaking a dead flower represents how far the speaker’s imagination has gone into fanciful associations. In relating his memory to a dead flower, he implies that it had lost its life before it was reconfigured by his imagination.
"Regard the moon,
La lune ne garde aucune rancune,”
This quote is a nod to the French symbolist poets Eliot admired, and translates to: “The moon bears no grudge.”
The moon is personified as an old, weak, sick woman who has “lost her memory.” In losing her memory, she has lost her history, meaning, and identity too—as the moon was the romantic symbol of innocence and love.
She is kindly, but lost, as she “smiles into corners” and “smooths the hair of the grass.” The craters of the moon are figured as pox marks. The moon here represents the connection between human culture and the natural world, which has decayed.
"Four o'clock,
Here is the number on the door.
Memory!
You have the key,"
In the final stanza, the speaker arrives at home, finally, at 4 AM. The street lamp continues to speak to him, up until he reaches his front door, and then directs him to the next lamp on the stair, and finally tells him exactly how to conduct his evening routine. He has no will.
The word “Memory!” on its own line here can be interpreted in two ways: Either it is a comment on the line before, meaning that he remembered the “number on the door,” or in a more abstract interpretation, it could be read with the following line: as “Memory! You have the key” meaning that memory is the key to something he seeks.
