1. The part of the brain concerned with the sense of hearing develops earlier and the nerve fibres found in this situation are myelinated[1] at an earlier period of development of the brain than the portion connected with the sense of movement of the muscles of articulation. [Footnote 1: The covering of the fibres by a sheath of phosphoretted fat serving to insulate the conductile portion of the nerve is an indication that the fibre has commenced to function as a conductor of nervous impulses.] 2. As a rule, the child's first ideas of language come through the sense of hearing; articulate speech is next evolved, in fact the child speaks only that which it has heard; it learns first to repeat the names of persons and objects with which it comes into relation, associating visual images with auditory symbols. An example of this was communicated by Darwin to Romanes. One of his children who was just beginning to speak, called a duck a "quack." By an appreciation of the resemblance of qualities it next extended the term "quack" to denote all birds and insects on the one hand, and all fluid objects on the other. Lastly, by a still more delicate appreciation of resemblance the child called all coins "quack" because on the back of a French sou it had seen the representation of an eagle (Romanes' "Mental Evolution in Man," p. 183). Later on, children who have been educated acquire a knowledge of the application of visual symbols, and how to represent them by drawing and writing, and associate them with persons and objects. 3. There is more definiteness of impression and readiness of recall for auditory than for articulatory motor sense feelings. 4. After the acquirement of speech by the child, auditory feelings are still necessary for articulate speech processes; for if it were not so, how could we explain the fact that a child up to the fifth or sixth year in full possession of speech will become dumb if it loses the sense of hearing from middle-ear disease, unless it be educated later by lip language. 5. Cases have been recorded of bilateral lesion of the auditory centre of the brain producing loss of hearing and loss of speech, the motor centres being unaffected. This is called Wernicke's sensory aphasia. The following case occurring in my own practice is probably the most complete instance recorded. CASE OF DEAFNESS ARISING FROM DESTRUCTION OF THE AUDITORY CENTRES IN THE BRAIN CAUSING LOSS OF SPEECH