Final answer:
The statement is an example of personification, which gives human traits to non-human subjects, such as the disease pneumonia in 'The Last Leaf'.
Step-by-step explanation:
The statement from "The Last Leaf" that "Mr. Pneumonia was not what you would call a chivalric old gentleman" is an example of personification.
This literary device is used to give human characteristics to non-human entities.
In this case, the illness pneumonia is characterized as an ungentlemanly entity, suggesting that it is callous and merciless, without the noble qualities of chivalry that would make it noble or fair.
By using personification, the author adds depth to the narrative, creating a more vivid and relatable image of the disease as a cruel adversary.