This is a detailed record of controlled objective observations on twenty-five normal infants from birth to 2 years of age. The author systematically applied a large number of tests at regular intervals in the homes of the patients. The results of the tests were supplemented by general observations. In this volume the author was interested in intellectual development. Like most tests on infants, the records are of physiologic development.
Several interesting and important conclusions are drawn. Among them are: 1. Human and animal infants follow the same general biologic laws, follow the same orderly sequence of development and adhere to the anatomic laws of developmental direction in that postural and motor controls begin headward and travel caudally. 2. This consistency of development in human and animal infants suggests the importance of maturation in the development of the behavior of infants. 3. New items of behavior emerge more rapidly during the