(animality) + _x_ (rational language) = _a_ and _a_. The passage in this chapter to which we reluctantly take exception is the following: “I actually heard Professor Vogt at Norwich (at the British Association meeting of 1868), in discussing certain cases of aphasia, declare before the whole physiological section: ‘_Je ne comprends pas la parole dans un homme qui ne parle pas_’――a declaration which manifestly showed that he was not qualified to form, still less to express, any opinion whatever on the subject.” Now, we are of opinion that, rightly understood and interpreted in the light of the most recent researches, these words convey a deep and significant truth. Dr. Mivart is anxious, in the interest of truth, to maintain intact and entire the essential difference between emotional and rational language, and this we believe he might best do by investigating and adapting the facts of aphasia. Aphasia declares that language-function is confined to some portion of the anterior convolution of the brain――a source or centre of nerve-power altogether distinct from the vesicular or gray portion of the cerebral substance which is concerned in the production of thought and all purely intellectual processes. This being the case, whenever we discover a lesion of the anterior convolution, and find it accompanied with impaired ability of speech, we also find inability to conceive such thoughts as those of which words are the sole symbol and sensible signs. The researches made by Trousseau, Hammond, and Ferrier prove that the faculty of language is thus localized, the anatomical region being somewhere in the neighborhood of the island of Reil; and though Brown-Séquard, a physiologist whose opinion is entitled to great consideration, differs from this view, the fact that more than five hundred cases as against thirteen favor the opinion is sufficient guarantee of its probable truth.