The patient had been shown twice in seminar for discussion of differentia] diagnosis between pithiatism and organic brain lesions. At first, two months after admission, the pattern was as follows: no peculiar troubles in thinking; impaired attention; poor spontaneous speech; general lack of initiative; no care for the self; behavior sometimes theatrical, apparently pithiatic; muscular hypertonia, aroused by the examination; gait uneaven, by short steps, subject falling often, in no predictable direction; tonic spells, decerebrate in type; poor bodily status. No neurophthalmic disorders (only the fundi examination was feasible, for lack in cooperation); mild alterations at the spinal fluid tests; tests for syphilis negative in the serum and in the spinal fluid. Provisional diagnosis: psychosis with brain lesions, probably in the orbital region or along fronto-ponto-cerebellar pathways. At the second time, three months later, seclusion was growing worse, lack of undertaking was most marked, the patient was completely unable to care for himself and remained conspurcated; gait troubles were accrued with astasia-abasia and trunk ataxia; cerebellar fits were more frequent; fluid examinations, still incomplete, and neurophthalmic data gave no new results; pneumoencephalography was not yet available. The pattern of intermixed organic troubles and pithiatic behavior led to a closer pathogenetic diagnosis: orbital syndrome due to cerebellar lesions probably. It was only five months after admission that proper fluid examination was available, and then rendered an etiologic diagnosis possible. The patient was then unable to walk and to take care of himself, and remained unalert. Diagnosis: neuropsychiatry orbital syndrome evoked by cerebellopontine disturbances; cysticercosis probably. Exitus eleven months after admission. Necropsy disclosed, as for the c.n.s., a bunch of cysticercus racemosus at the cerebello-pontine region, at right (fig. 1); leptomeninges were somewhat thick at the basis until the temporal lobes. No alteration of the frontal lobes or elsewhere, macro-scopically and histologically as well (at Nissl and Weil stains). As for the pathogenesis, the orbital patterns, in sensu Kleist's, consisted of lack in maintaining mental alertness and the initiative (Ausdauer), in the instinctual drives (gesinnungsmassige Handlungen), as well as of the theatrical troubles of character (Gesinnung). Neurological and neuro-vegetative troubles were to be ascribed to paleo-cerebellar regulations, in the authors' mind.