He describes a patient whose moral reasoning has been disrupted by surgery to separate the hemispheres, who then judges that it is acceptable for a waitress to serve sesame seeds to someone she thinks is allergic to them, but who is not.
There is nothing worse than a formerly promiscuous aunt now on a crusade for moral rectitude playing the harpy and scold in the sick room, elbowing the doctor aside to upbraid the patient with inappropriately timed, self-righteous sermons.