One or both parents of asthmatics is usually a dominating person who makes the child feel guilty for 'defiant' excretory acts. Excretory fantasies then come to colour the whole later development of infantile sexuality, including the wish to grow up. These fantasies stimulate the excretory mucous membranes, and this in turn sensitizes the respiratory mucous membrane, just as physical stimulation of the excretory membranes stimulates respiration. The nascent excretory aggression arouses fears of excretory retaliation, but now upon the respiratory apparatus, which behaves as though it were really being assaulted with noxious substances.