[Illustration: $1] =Symptoms.= The dominant symptom is difficulty in breathing, both when moving and eating, a difficulty which is sometimes so considerable as to cause snoring respiration or roaring. Nevertheless, examination of the trachea and of the lung, visual examination of the lower portions of the nasal cavities, and manual examination of the pharynx, larynx and glottis give only negative results. It may even happen, as occurred in the case from which the illustration herewith was taken, that percussion of the maxillary sinus reveals normal resonance. In the case of tumours of small size the forehead is not deformed. When, on the other hand, the tumour partly obstructs the nasal cavities it may thrust on one side the septum nasi and externally cause well-marked asymmetry of the face. Sero-mucous or muco-purulent discharge then occurs. =The diagnosis= is somewhat difficult, for continuous or temporary roaring (or at any rate difficulty of respiration), being the dominant symptom, must be distinguished from roaring due to a laryngeal lesion like paralysis or tumour formation, from perilaryngeal compression due to enlarged retro-pharyngeal glands, and from tracheal or pulmonary lesions; and its origin must be located in the nasal cavities. [Illustration: $1] =The prognosis= is grave, in consequence of the difficulty of exploring the depth of these cavities and of the possible nature of the tumour. Nevertheless, in the case of simple myxomata permanent recovery usually follows extirpation. =Treatment= is confined to extirpation, which is quite possible in the case of pedunculated tumours; in the case of sessile tumours free trepanation of the roof of the nasal cavities becomes necessary. The operation is quite safe. PURULENT COLLECTIONS IN THE NASAL SINUSES. NASAL GLEET. From the clinical point of view two varieties of this condition may be distinguished—inflammation of the mucous membrane of the maxillary sinus and inflammation of the mucous membrane of the frontal sinus and of the horn core. These forms of inflammation frequently lead to suppuration. The pus collects in the depressions and divisions of the frontal or maxillary sinus. PURULENT COLLECTIONS IN THE FRONTAL SINUS. =Causation.= In the majority of cases inflammation of the mucous membrane of the frontal sinus is produced by external causes: fractures of the horns and horn core accompanied by hæmorrhage into the horn core; fractures of the horn with exposure of the sinus of the horn core; wounds and violent blows on the occipital region or the frontal bone; cracks or depressions of the external wall of the sinus, etc. In all these cases, whether blood is effused or the mucous membrane of the sinus is merely infiltrated with serum, infection may be produced by germs being deposited from the air passing through the nasal cavities and causing suppuration.