SummaryReport of a case of hysterical dyspnea in a female of 21 years, with moderate tachypnea and pseudo-spasm of the larynx. The patient was cured by isolation.Clinical and physiological analysis of the case prove the occurence of moderate overventilation of strictly limited sectors of the lungs (apex). Light and chronic acapnia and alcalosis result therefrom.To account for absence of cyanosis and true dyspnea, redistribution of the blood’s circulation within the lungs has been postulated