Professor Preyer considers that the development of the power of using language is the most prominent index to the unfolding of the intellect. He differs with Professor Max Mueller, however, on the question whether the operation of thinking can be carried on without the use of words (see the recent elaborate work of the latter on "The Science of Thought"). At my suggestion, the painstaking translator of this book has prepared a full conspectus, showing the results of Professor Preyer's careful observations in a chronological order, arranged by months. This considerable labor will render the book more practical, inasmuch as it will enable each reader to see at a glance the items of development of the child in the several departments brought together in epochs. This makes it possible to institute comparative observations under the guidance of Professor Preyer's method. I think that I do not exaggerate the value of this conspectus when I say that it doubles the value of the work to the reader. WILLIAM T. HARRIS. CONCORD, MASS., _November, 1888_. CONTENTS. PAGE PREFACE BY THE EDITOR v CONSPECTUS SHOWING THE PROGRESS OF THE CHILD BY MONTHS ix THIRD PART. _DEVELOPMENT OF THE INTELLECT._ CHAPTER XVI.--DEVELOPMENT OF THE CHILD'S INTELLECT INDEPENDENT OF LANGUAGE 3 XVII.--LEARNING TO SPEAK 33 1. Disturbances of Speech in Adults 34 (1) Periphero-Impressive or Perceptive Disturbances, 36. (2) Central Disturbances, 37. (3) Periphero-Expressive or Articulatory Disturbances, 38. 2. The Organic Conditions of Learning to Speak 42 3. Parallel between the Disturbances of Speech in Adults and the Imperfections of Speech in the Child 45 I. Lalopathy, 47. A. The Impressive Peripheral Processes disturbed--Deafness, 47. B. The Central Processes disturbed--Dysphasia, 47. (1) The Sensory Processes centrally disturbed, 47. (2) The Sensori-motor Processes of Diction disturbed, 48. (3) The Motor Processes centrally disturbed, 49. C. The Expressive Peripheral Processes disturbed, 54. (1) Dyslalia and Alalia, 54. (2) Literal Pararthria or Paralalia, 56. (3) Bradylalia, or Bradyarthria, 57. II. Dysphasia, 58. III. Dysmimia, 62.