Describe the incident were Jerome realises that he is ill with almost all known diseases ?

Clarisse makes Montag see the truth of his society. After his meeting with Clarisse, Montag fees a sense of enlightenment which makes him see just how grey and black his society is. He sees there is nothing vibrant, passionate, or intelligent in his world. Montag feels the urge to tear down his emotionally toxic diseased world and begin again.