eleven patients had a positive response, encouraging his work (see Gazdag et al., 2009). In his autobiography, he recalls the case of a 33-year-old patient with severe catatonia who began his treatment on January 23, 1934. After just five sessions, catatonia and psychotic symptoms were abolished. Increasing his sample size to twenty-six patients, Meduna achieved recovery in ten and improvement in three more. A major factor in Meduna's achievement was his selection of patients: nine of the first eleven were catatonic. Catatonia is a syndrome that is remarkably responsive to induced seizures. The serendipity that catatonia was considered schizophrenia at the time made his discovery possible. Early on, Meduna replaced camphor with pentylenetetrazol, an intravenous agent that typically induced seizures within a few minutes, compared with the long delay of 15 to 45 minutes after intramuscular administration of camphor. In addition to being a powerful analeptic drug, pentylenetetrazol is a potent cardiac and respiratory stimulant; consequently, patients experienced sensations most considered unpleasant. They were completely alert until unconsciousness from the convulsion set in, and unlike with electroconvulsive therapy, which caused retrograde amnesia that ameliorated any unpleasant memory of that treatment, patients remembered any sensations that preceded the Metrazol-induced convulsion. Meduna and some other physicians felt that the fear reaction may have been part of the reason the treatment was successful in some patients. Published research He first published his results in 1935 and then his major text in 1937. Die Konvulsionstherapie der Schizophrenie describes the results in 110 patients. Of these patients about half recovered. The results were much better for patients who were ill less than a year compared to those who had been ill for many years. After his results were quickly reproduced in many other centers around the world, this form of therapy became widely used and recognized as the first effective treatment for schizophrenia.(A parallel development was insulin coma therapy.) A more facile form of induction of seizures, using electricity instead of chemicals, was developed by the Italian psychiatrists Ugo Cerletti and Lucio Bini. They treated their first patient with ECT in May 1938 and by the mid-1940s, electricity had replaced Metrazole as the induction agent. Carbon dioxide therapy Meduna also developed carbon dioxide therapy in which the patient breathed a gaseous mixture of 30% carbon dioxide and 70% oxygen called carboxygen or carbogen (and sometimes "Meduna's Mixture") that was designed to provoke a powerful feeling