Special methods of diagnosis as follows are mentioned: transillumination; examination of upper teeth; catheterization of the ostium, maxillares, naso-frontal canal, and outlet of the sphenoidal sinuses; external examination of antrum and frontal sinuses; exploratory puncture of the antrum through the inferior meatus, alveolar process, or canine fossa. Diagnosis of ethmoiditis is principally by exclusion. Treatment of the accessory sinuses may be summed up under the following indications: (_a_) removal of the cause; (_b_) evacuation and drainage of pus; (c) antiseptic irrigation; (d) removal of morbid material, when present. PALMER. =Williamson, R. T.—Remarks on the Diagnosis and Prognosis in One Hundred Cases of Double Optic Neuritis with Headache.=—_Lancet_, May 12, 1900. The detection of optic neuritis is of the greatest importance in the diagnosis of cerebral affections. Nevertheless, in certain cases of double optic neuritis with headache considerable caution is necessary before coming to a conclusion as to the exact nature of the disease. Though these two symptoms are present in the majority of cases of brain tumor and are so frequently due to this cause they are also met with in other diseases. In some cases of granular kidney, for example, the patient comes under treatment for headache and failure of vision; and ophthalmoscopic examination may reveal intense optic neuritis like that of cerebral tumor (neuritic form of albuminuric retinitis). At first the symptoms appear to indicate cerebral tumor, but a careful examination of the urine and cardio-vascular system will clearly reveal the cause. Limited space does not permit an enumeration of all the causes of double optic neuritis with headache. The results of the examination of one hundred cases presenting these two symptoms reveal, however, several points of interest. Most of these cases have been seen by us conjointly; some were seen separately, whilst others (in Groups I. to VIII.) were examined by one of us (R. T. W.) whilst holding the post of medical registrar at the Manchester Royal Infirmary. For permission to include the latter amongst our cases we are indebted to the medical board of that hospital. With respect to the diagnosis and termination these one hundred cases may be grouped as follows: I. Brain tumor, verified by necropsy, 27. II. Cases terminating fatally; probably, majority due to brain tumor; but no necropsy obtained, 27. III. General symptoms of brain tumor; but necropsy revealed distention of the ventricles of the brain with fluid; no tumor (serous meningitis of ventricles), 2. IV. Cerebral abscess (fatal), 3. V. Tuberculous meningitis (fatal), 2. VI. Chronic interstitial nephritis; neuritic form of albuminuric retinitis (fatal), 3. VII. Toxic conditions and blood diseases: Chronic lead poisoning, 3. Ulcerative endocarditis, (fatal), 1. Purpura hemorrhagica (fatal), 1. Henoch’s purpura (fatal), 1. Chlorosis with cerebral symptoms (recovery), 3.