The clinical spectrum of this remarkable non-syphilitic spirochaetosis (spirochaeta infection) of the nervous system is described in light of 53 further cases with reference to our earlier description of 47 cases. As the etiological diagnosis is not possible in all cases the knowledge of clinical courses is especially important. Males are affected almost twice as often as women. The disease is especially prevalent in the sixth decade. Usually, the syndrome begins in the warm season with exquisite pain and other sensory irritations in combination with marked malaise. Initial signs during the winter as well as painless clinical courses were also noted. About one half of the patients remembered contact with arthropodes or a chronic migrating erythema. In most cases (95%), asymmetrical peripheral signs followed the painful stage. More than two thirds of the patients showed affection of cranial nerves, usually facial palsy. Twenty percent demonstrated paresis of the extremities alone, the combination of involvement of cranial nerves and extremities was noted in one third of the cases. The sensory signs were usually only mild. Occasionally, the neurological impairment was limited to isolated sensory impairment. In contrast to the closely related Lyme disease, central nervous affection as well as cardiac and arthritic involvement is rare: 34 percent demonstrated mild psychopathological impairment; in one case a Babinski-phenomenon was elicited. Knee joint pain and gonarthritis were found in one case each. Even though meningeal signs were usually absent, the CSF showed alterations suggestive of chronic lymphocytic meningitis in all cases. At the same time, local synthesis of all three immune globulins was documented, especially of IgM (85%).