how do the three friends describe to each other their diseases they think they have

The narrator, J., is smoking in his room with his friends, Georgeand William Samuel Harris, and his dog Montmorency. The men, all hypochondriacs, are chatting about their latest illnesses, each man certain that he is in danger of death or serious disease.

In a flashback, 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).

J. still believes that he suffers from every disease, but he is especially concerned about his ‘liver condition’ – the main symptom of which is “a general disinclination to work of any kind” (10).