_Intracranial pressure_, being increased in brain abscess, will cause the cerebrospinal fluid to be increased and found to be so by spinal puncture, although no pus cells or micro-organisms will be found, unless there is also a concomitant diffuse septic meningitis or ventricular infection present. The ocular symptoms of intracranial pressure, such as pupillary (often one large and one small) and choked disk, are usually present. The _pulse rate_ and _respiration_ will be affected, as in brain tumor, according to the size of the abscess. The larger the abscess the slower the pulse and respiration. The temperature, as well as the pulse and respiration, will vary as to whether the abscess be intradural or extradural. Intradural abscesses will frequently cause considerable rise of temperature, and acceleration of the pulse and respiration, and a remission when the abscess has become partially walled off. As soon as a fresh invasion of brain tissue takes place another rise of temperature, etc., occurs. _Projectile vomiting_ is, as in brain tumor, quite frequently encountered. _The Röntgenogram_, especially a stereoscopic one, will be of some value in cases where through its chronicity a change of bone by pressure has taken place, or if one may follow the path of necrosis from the nasal accessory sinuses or the middle ear and mastoid process towards the brain. I will state, however, as I have stated on several occasions before, that not too much emphasis should be laid on the diagnostic value of the _x_-ray in intracranial lesions, especially abscess. I have been disappointed in this great method of diagnosis (_x_-ray) and much annoyed at the positiveness of some observers without sufficient evidence. As in sinus thrombosis, so in brain abscess one should not hesitate in the exploratory operation, because waiting too long will often reduce the patient’s ability to stand an operation later on. Should one not find the abscess, then the decompression has done a great deal to prevent destruction of brain tissue by pressure, besides the patient will be very much relieved of the severe head-pains. This may be said also of spinal punctures. In this way one may wait for development of localization for another operation. In conclusion, I would like to repeat the words of Prof. Neumann as to the differential diagnosis between meningitis, sinus thrombosis, and brain abscess: “A patient that has meningitis is one that wishes to be left alone and allowed to sleep, although when roused is not particularly irritable. If he has brain abscess then he is constantly very irritable and difficult to manage, while a patient that has sinus thrombosis when he is free from the chill and fever is very pleasant, apparently well.” THE TREATMENT OF GONORRHEAL OPHTHALMIA Arthur Edward Smith, M. D. MINNEAPOLIS