Dem/o -----> people ------> greek----> democracy --- government of the people; democraphic --- the study of people;
epidemic--- spreading among people in a region
Through his skill or the way of writing
the glistening snow cover the streets after the snowstorm in New England.
It suggests that Groucho believes the writer of the original letter knows as little about the city of Casa- blanca (his history is filled with absurd details) as he knows about how different the Marx Brothers' film A Night in Casablanca would be from the famous Casablanca.