(_a_) =Temporo-sphenoidal abscess.= The abscess occupies one of the so-called ‘silent’ areas of the brain, an area merely exercising a word-hearing faculty (see p. 163). Insomuch, however, as auditory power is already impaired or lost from the disease existent in the middle ear, it follows that a temporo-sphenoidal abscess may not give rise to any localizing symptoms whatever. Definite motor symptoms will only be observed when an abscess of considerable size exercises an upward pressure on the lower motor areas, or an inward pressure on the internal capsule. Thus, (1) when the pressure effects are exercised in the _upward_ direction the lower motor areas will suffer with resultant paresis or paralysis of the muscles of the contra-lateral face and upper extremity, and, if the abscess be situated on the left side, aphasia may also be present. And (2) when the pressure is exerted mainly in the _inward_ direction so as to interfere with the internal capsule the motor areas are affected in the reverse order, lower extremity first and face last. [Illustration: FIG. 76. TO ILLUSTRATE THE PRESSURE EFFECTS OF A TEMPORO-SPHENOIDAL ABSCESS:--(1) _upward_ pressure on the lower cortical motor area, and (2) _inward_ pressure on the internal capsule. T.S., Temporo-sphenoidal abscess; _a._, Cortical area for lower extremity; _b._, Cortical area for upper extremity; _c._, Cortical area for face; C.N., Caudate nucleus; L.N., Lenticular nucleus; I.C., Internal capsule; O.T., Optic thalamus.] _Aphasia_ will partake of the motor or sensory type according to the situation of the abscess. Thus, motor aphasia indicates pressure on Broca’s area, sensory points to the involvement of the region of the angular gyrus (see p. 163). According to Schmiegelow, some type of aphasia was present in 23 out of 54 cases of otitic temporo-sphenoidal abscess. _Facial paralysis_, whether due to inward or upward pressure, is of the incomplete or cortical type, the upper face-muscles escaping or being but slightly affected. No difficulty need be experienced in differentiating between the ipso-lateral paralysis which results from destruction of the facial nerve in the aqueductus Fallopii and the contra-lateral palsy dependent on the cortical lesion. Pressure may also be exercised on the post-Rolandic sensory areas and on the tracts that evolve therefrom, but the general condition of the patient seldom allows of any accurate diagnosis with respect to sensory involvement in general.