When the great influenza epidemic struck Philadelphia in 1918, the author was just starting his third year at the University of Pennsylvania School of Medicine. After a single lecture on influenza, classes for the third and fourth year students were suspended while he and his mates manned an emergency hospital, in which they worked under little or no medical supervision and in the presence of an alarming patient mortality. This essay describes what happened in the hospital, and in the city as a whole, during the pandemic. Certain features of the clinical course of most patients permit the hope that modern therapy will prevent a repetition of the horrendous mortality.