It is clear that the brain was not wholly normal, exhibiting a general induration due in part to subpial gliosis and in part doubtless to perivascular gliosis. =Microscopically= the tissues showed features of great interest, especially multiple focal neuroglia cell proliferations of a perivascular distribution, considerable subpial fibrillar gliosis of an unusually focal type, and a rather general subpial cellular =gliosis=. Histologically, it seemed that this chronic progressive process had started, not so much in relation with dying nerve cells, as in relation with blood vessels. The =perivascular= deposits of neuroglia cells were confined almost exclusively to the infragranular cortex layers. It seems plain that the diagnosis of general paresis was not justified. It is probable that the diagnosis of neurosyphilis is not justified. The explanation may be that now and then cases of cerebral sclerosis may clinically imitate the neurosyphilitic process. It must be borne in mind that the diagnosis in this case was made, like the other cases at head of Part III, without the advantage of modern systematic methods. Clinically speaking, of course, there was no definite Argyll-Robertson pupil, although the consensual reaction, slight on the left side, was absent in the right pupil. The general picture appeared to be one of the so-called demented form of paretic neurosyphilis. =Differential diagnosis between NEUROSYPHILIS and NEURASTHENIA.= =Case 45.= Albert Robinson, a man of 28 years, was shipwrecked on one of the Great Lakes. The ship was on the rocks for eight days, and Robinson was under a great strain. Ever after the wreck, Robinson had felt severe pain in the head, neck, and back, and a feeling of great weakness whenever he exerted himself physically or mentally, and seven months after the wreck, he had several attacks of fainting. For a number of weeks he had worried a good deal about his inability to make money, especially as money was badly needed on account of his wife’s approaching confinement. A few days before entrance, Robinson had become very forgetful, and was unable to recall, the night before entrance, where he had been during the day. On the whole, however, on mental examination no actual evidence of memory defect could be shown to exist. =Physically=, Robinson was entirely negative, except for some hard glands in each groin. =Mentally=, there was little to show except depression, worry over his financial condition, and his inability to work. The serum W. R. proved negative. =Diagnosis=: On the whole, the diagnosis of psychoneurosis (see case Harrison (9)) due to the shock at the time of the shipwreck seemed to be proper. To be sure, the patient gave a history of a chancre at 25, treated for two years, after which he was declared cured. However, following up the clue of admitted syphilis, rigorous questioning elicited the fact that a few months before there had been diplopia, lasting part of a day.