why did the narrator fell complled to see his doctor friend ? what prescription did the letter give him and why ?

J. recollects how he once went to the British Museum to research a treatment for his hay fever, and after reading about diseases, convinced himself that he was suffering from every illness known to man except for housemaid’s knee. J.’s doctor, clearly recognizing the man's paranoia, prescribed him beefsteak, beer, walking, and good sleep habits, and urged him not to “stuff up your head with things you don’t understand” (10).