Data.—Type cases of post-influenzal schizophrenia arranged in ascending order of severity from delirium to dementia præcox. Pertinent literature.Deductions.—Dementia præcox is apparently sometimes a chronic delirium (schizophrenia deliriosa). Delirium is apparently sometimes an acute dementia praæcox (delirium schizophrenoides). Both forms are (sometimes) reversible.Inductions.—These two forms may represent an identical process manifested by varying degrees of reversibility of the schizophrenia. The concept "Reversible Schizophrenia" (cf. the term "delirium schizophrenoides") is not a mere nosological quibble, since it may affect our conception of the nature of dementia præcox. It implies conditions of reversibility which we may discover to be under our control!