But although the inflammatory changes in the shape of lymphocytosis were relatively more prominent in the spinal cord than in the cortex, yet the cortex yielded evidence of an exceedingly marked destructive process. Perhaps no layer of any of the areas of the cortex examined failed to show some atrophic alteration. The upper layers of the cortex were everywhere more severely diseased than the lower layers. Here we are dealing with an instance of an active meningomyelitis and subcortical encephalitis. It is, of course, probable that the W. R., had it been performed, would have been positive in this case. On the basis of the histology, we are inclined to regard the clinical picture in this case as belonging among cases of NON-PARETIC DIFFUSE NEUROSYPHILIS. This case, as also the next several, is especially instructive in teaching the difficulty in differentiating paretic and non-paretic neurosyphilis. Not only is this difficulty met in clinical diagnosis, but in pathological diagnosis as well. The histological diagnosis depends in large part on the work of the Nissl-Alzheimer school, which has received great recognition. At the present time, however, there is beginning to be considerable doubt as to the entire validity of this teaching. At any rate there are many borderline cases in which the differentiation is well nigh impossible. In this case note chronic meningoencephalitis, with cortical degeneration, in the absence of plasmocytosis. From the clinical standpoint the intensity of the W. R., the character of the gold sol reaction, and the result of therapy have added new points in differentiation. Much more work controlled by autopsies is still needed, however, to put us on sure ground in borderline cases. =VASCULAR NEUROSYPHILIS(?) versus PARETIC NEUROSYPHILIS (“general paresis”). Autopsy.= =Case 40.= Case 40 like Case 41 was an error in the diagnosis of general paresis which might be regarded as academic rather than practical. Both were cases of arteriosclerotic brain disease with severe cerebellar involvement. Case 40 had a spinal cord that was not quite normal. There was a tabetiform lesion in the cervical spinal cord (not elsewhere), together with a unilateral degeneration suggesting in some respects a radicular origin. The most striking feature, however, of Case 40 as in Case 41, was a lesion of the cerebellum. In Case 40 the dentate nuclei were in large part destroyed by cysts of softening, although the cerebellar cortex was fairly well preserved on both sides. The details of Case 40 are as follows: H. F., male, gear maker, born 1850. =Heredity.= Maternal grandmother insane. Mother insane at 52, became demented and lost use of limbs, died at 71. Aunt insane.