4. What is the meaning and value of the so-called provocative salvarsan injection? In practice, there may be a series of negative W. R.’s in the blood serum before a positive reaction is finally obtained, owing to technical difficulties or biological peculiarities. Where intensive work is being done upon the neurosyphilis problem, it is beyond question desirable to make the W. R. test upon at least three separate samples of blood drawn at intervals, for the second or third test may prove positive. This situation makes the interpretation of the so-called provocative salvarsan injection exceedingly doubtful; that is, the reaction might have been positive on repetition without the injection of salvarsan. The present case, as above stated, failed to yield a serum W. R. even after repeated tests and the “provocative.” 5. What is the significance of the irregular pupils in this group? Paretic neurosyphilis shows inequality of the pupils in a high per cent of cases. Irregularity of outline of the pupils is commonly thought to be an important sign and to suggest neurosyphilis. It is true that many cases of pupillary irregularity are syphilitic, but the sign is of little or no differential value since congenital malformations and relics of old injuries and adhesions may produce effects identical with those of neurosyphilis. =DIFFUSE (that is, meningovasculoparenchymatous[5]) NEUROSYPHILIS is typically associated with six positive tests (serum Wassermann reaction, fluid Wassermann reaction, spinal fluid gold sol reaction, pleocytosis, positive globulin, excessive albumin); but one or more, and frequently several, of these tests are likely to run mild as compared with the tests in PARETIC NEUROSYPHILIS (“general paresis”). The clinical course of the diffuse (and especially the meningovascular) cases is likely to be protracted, with a good prognosis as to life (barring fatal vascular insults).= =Case 14.= We shall present the case of John Jackson, a surveyor, 31 years of age, suffering from a left hemiplegia, with this in mind: To exhibit difficulties in diagnosis in the presence of an embarrassment of symptomatic riches. The patient arrived at the hospital, in the first place, because he had been threatening a woman who lived next door to him. He believed that this neighbor had been talking about him and circulating reports against him. Excited by these ideas, he had threatened to cut her throat.