The symptomatology of brain syphilis necessarily varies with the nature, extent and location of the lesion. In the earlier stages of a diffuse meningitis the prominent symptoms to be expected first are headache and dizziness. In an individual with a definite specific history a persistence of such symptoms should suggest salvarsan therapy. Vomiting is a common complication. Cranial nerve palsies, optic neuritis or hemiplegia in such a case would, of course, be conclusive. Stuporous, confused or delirious states may occur, with or without hallucinations. When the syphilitic process is an extensive one with a widespread meningitis or gummatous involvement of the base, numerous focal symptoms are to be expected. Choked disc, optic tract lesions, paralysis of the ocular muscles, facial neuralgias, facial palsies, deafness, or anesthesias may occur. Mental deterioration naturally advances with the progress of the disease, but the personality is much better preserved than in general paresis. Periods of unconsciousness are not infrequent and convulsive attacks may appear. These may be general or local and paralyses often follow. These may assume the form of a hemiplegia or may involve only certain groups of muscles. Ptosis is often noted. Paralysis of other eye muscles is common, and pupillary rigidity is sometimes a symptom. Hemianopsia and diplopia are often observed: An important feature of the disease is the fact that these conditions are more or less transitory and rarely become permanent. Apoplectiform attacks followed by hemiplegia are results of gummatous growth or may be associated with areas of softening. These are due to vascular disturbances. Aphasia is not an unusual occurrence. Hemiplegias appearing suddenly in individuals under forty years of age are likely to be of specific origin. Epilepsies developing in later years should always be viewed with suspicion. The Korsakow symptom complex has been found in some cases of brain syphilis. Memory defect is present in most instances. When a marked mental deterioration takes place it is usually late in the disease. Argyll-Robertson pupils are infrequent in cerebral syphilis. Speech defect is practically never so conspicuous as it is in general paresis. Writing difficulties are also much less marked. Euphoria and grandiose delusions occasionally occur in brain syphilis but much less frequently than in general paresis. Hemiplegias, when they occur, are much more likely to be permanent than they are in general paresis. Paranoid complexes are sometimes clinical features of the disease and if they persist strongly suggest syphilis rather than paresis.