With regard to any special points in treatment, it is obvious that syringing of ear or nose is absolutely contra-indicated. The cavities should be _lightly_ plugged with gauze, the dressings to be renewed as soon as they are soaked. The patient must also be prevented from interfering with the dressings. With regard to the routine use of urotropin to guard against the advent of meningitis, see p. 116. =Escape of brain-matter from the nose.= This diagnostic symptom is of very rare occurrence. For its development the following factors are requisite:-- Great comminution and destruction of the anterior fossa. Severe local laceration of the brain (frontal lobes). A copious discharge of blood and cerebro-spinal fluid. A general increase in the intracranial pressure. One case only of this nature has come under my own observation, that of a man whose right nostril was blocked with brain substance. He died shortly after admission into the hospital, and at the post-mortem examination the above conditions were found. =Escape of air from the air-sinuses into the surrounding regions.= When the fracture involves the frontal, ethmoidal, and mastoid sinuses, any sudden increase of the intrasinus air-pressure, such as is caused by sneezing, blowing of the nose, &c., may force air into the surrounding tissues. A distinction must be made between those cases in which the pericranium overlying the seat of fracture is torn and those in which it remains intact. In the former case, the escaping air may spread widely into the neighbouring loose tissues, leading to a condition of ‘surgical emphysema’. In the second case, the air remains confined to a smaller area, giving rise to a soft, more or less rounded swelling. Gentle palpation of this swelling imparts to the fingers that crackling sensation peculiar to the condition. Firm pressure results in diminution in the size of the tumour, the contained air being forced back into the sinus cavity. Such localized collections of air are known as ‘pneumatoceles’. As regards the special _treatment_ of these conditions, the patient must, in the first case, be warned against straining of all sorts. Pneumatoceles require no other treatment. The condition soon disappears if the patient recovers. In widespread surgical emphysema, an incision should be made over the injured sinus, thus allowing of the direct escape of the air expelled from that sinus. =The involvement of nerves.= The following nerves may be involved in anterior fossa fractures:--