A letter from Roderick Usher which gave a nervous agitation in itself was the basic outline that summarizes this passage.
Explanation:
Roderick Usher was one of narrator's companions in his boyhood. It has been several years since he last met Roderick. A letter, which was very personal, was received by the narrator now. In the letter, there was a message about a mental illness that depressed him both, physically and psychologically.
In the letter, the narrator could feel how empty and lonely Roderick was feeling because of the words he used to express his pain.
The statement: An earnest desire to see me, as his best and indeed his only personal friend, a view of attempting some alleviation of his malady (grief) - best describes the passage
