The exhaustive conditions in a large group of more severe cases are ushered in by a delirium or confusional state with a depressed mood. There is first a slight anxiety. Self-accusation and persecutory ideas appear early. Hallucinations of hearing and vision develop. The patients soon become clouded, inattentive, show difficulty of thought and loss of memory, with mental dulness. All grasp upon their surroundings is lost, they fail to recognize members of the family, and answer questions unintelligently. They have no appreciation of their condition and no memory for events. The mood is indifferent, apathetic or whining. It may be irritable, quarrelsome or violent. Usually they lie in bed and are entirely apathetic. Sometimes they show automatic movements and have to be fed. The conversation is often incoherent and meaningless. They are inclined to be emotional. Sleep is usually interfered with and they are restless at night. The appetite is lost. Occasionally evidences of brain lesions appear with paralyses, speech disturbance or epileptiform seizures. The duration is usually a matter of a number of months. At autopsy grave cell alterations and glia reactions are common. Rod cells are also found. Endothelial proliferation is frequently observed in the vessel walls. Some cases terminate in a chronic condition which may improve somewhat in time. There may be a persistent emotional and mental enfeeblement with indifference, loss of memory, lack of judgment and impairment of will. These "acute dementias" represent the terminal stages of cortical infectious processes. They have been observed after typhoid, rheumatism, erysipelas, cholera, smallpox and malaria. Usually after tubercular peritonitis or articular rheumatism there is a simple mental enfeeblement, while erysipelas is usually accompanied by mild excitements and an elated mood. The typhoid cases usually showed irritability, with outbursts of anger and confusional states with hallucinations and delusions. They occasionally terminate in more chronic conditions with permanent deterioration. After typhoid, influenza and septic infections, Korsakow's "cerebropathica psychica toxaemica" sometimes occurs. This is the polyneuritic psychosis similar to that caused by alcohol. There is, however, a delirium or stupor at the same time. The post-rheumatic psychoses have been studied exhaustively by Knauer.[266] Stuporous attacks were found in ninety-three per cent of his cases, following acute infections. He describes four groups showing psychotic manifestations:— 1. Anxious delirious excitements followed by stupor. 2. Excitements alternating with stupor. 3. Stuporous depression throughout. 4. Amentia-like excitements throughout.