Although the above statements have not altogether been confirmed by cases that have come under my observation, yet, coming from such a source, they must be accepted unless refuted. Bianchi states that, after extirpation of the frontal lobe of the ape, the whole intellectual life of the animal is changed. Perception, attention, inhibition, and in particular memory and association are enfeebled. The psychical tone is lowered; the ape lacks initiative, courage, and spirit. Laceration of the under aspect of the lobe may, by direct involvement of the olfactory region, interfere with the faculties of smell and taste. _Localizing to those parts that minister to the function of speech._ The condition of the patient usually prevents one from obtaining early information as to the power of speech. Isolated lesions of the posterior part of the third left frontal convolution result in _motor aphasia_, a condition characterized by the inability on the part of the patient to speak, in spite of the fact that comprehension is unimpaired. The brain-injury is, however, seldom so defined as to be characterized by loss of speech without other phenomena. In very close relation to the area responsible for speech is the _writing_ centre, situated at the posterior end of the middle frontal gyrus, near the centre for the movements of the hands and fingers. Injury to this centre results in _agraphia_ and _alexia_. _Word-deafness_ results from lesions implicating the upper temporo-sphenoidal lobe, and _word-blindness_ from injuries to the supramarginal and angular gyri (see Fig. 57). [Illustration: FIG. 57. THE AREAS CONCERNED IN SPEECH EXPRESSION.] Phelps pointed out that the lesion must be an extensive one if the symptoms included under the term _sensory aphasia_ (word-blindness, word-deafness) are to be evolved. No localized injury to any small area suffices, and the cortex must be deeply involved. Lacerations of the brain are usually of so gross a nature that further differentiation is seldom to be obtained. Here it might be noted that the cortical centres responsible for speech and its accessories, word-seeing, word-writing, and possibly word-hearing, are all situated on the left side in normal right-handed individuals. The corresponding areas on the right side may be regarded as ‘silent’ areas, and may be utilized, if desired, for decompression purposes. No operation, with that purpose in view, should be carried out, however, unless the surgeon is assured that the patient is right-handed in his actions. A case has recently come to my knowledge where a right-parietal decompression operation was carried out with disastrous results.