Hypnotic suggestion

After listening to Stephen's antisemitic song in Ithaca, Bloom ponders a multitude of conditions capable of producing dangerously aberrant behavior in human beings. The list concludes with "hypnotic suggestion and somnambulism." As subsequent paragraphs explain, he is thinking not of hypnosis in the usual sense but of several different sleep disorders, known collectively as parasomnias, which he and his daughter Milly have experienced. Bloom's hunch about how closely these conditions are related is spot on, but his fear of them (expressed later in the chapter by a reference to "malignant agencies") is somewhat exaggerated. 

John Hunt 2021

Representation of a child with night terrors. Source: theswaddle.com.

The Nightmare, 1791 oil on canvas painting by Henry Fuseli held in the Detroit Institute of Arts. Source: Wikimedia Commons.

My Dream, My Bad Dream, 1915 work by Fritz Schwimbeck thought to depict sleep paralysis. Source: Wikimedia Commons.

Source: www.sleepdisordersresource.com.

Source: www.psychiatrictimes.com.