Intravenous injection of synthetic mescaline was used in a group of schizophrenic patients and on "normal" voluntary controls. The changes produced by mescaline in "normals" were described. In addition, the observations were made that mescaline is able to underscore in patients suffering from schizophrenia their schizophrenic symptoms or able to precipitate schizophrenic psychoses in persons suffering from latent schizophrenia. Different "therapeutic measures" were discussed as applied to the mescaline-produced abnormal mental states.Mescaline was also given to a number of patients before and after psychosurgery. It was found that with mescaline it was possible to reactivate the psychosis in patients who improved after psychosurgery but that their response to the drug was quantitatively less conspicuous than before.Abstract Teaser