How does Saul Bellow use imagery in Humboldt's Gift?

Imagery:

"I dreamed that we met at Whelan's Drugstore on the comer of Sixth and Eighth in Greenwich Village. He was not the stricken leaden swollen man I had seen on Forty-Sixth Street, but still the stout normal Humboldt of middle life. He was sitting beside me at the soda fountain with a Coke. I burst into tears. I said, 'Where have you been? I thought you were dead."'