The embryology of the child-soul has been known in a general way for thousands of years, and has been an object of keen interest to all observant parents and teachers; but it was not until about twenty years ago that a strictly scientific study was made of this remarkable and important phenomenon. In 1884 Kussmaul published his _Untersuchungen über das Seelenleben des neugeborenen Menschen_, and in 1882 W. Preyer published his _Mind of the Child_ [English translation; Dr. J. Sully has several works on the same subject]. From the careful manuals which these and other observers have published, it is clear that the new-born infant not only has no reason or consciousness, but is also deaf, and only gradually develops its sense and thought-centres. It is only by gradual contact with the outer world that these functions successively appear, such as speech, laughing, etc.; later still come the power of association, the forming of concepts and words, etc. Recent anatomic observations quite accord with these physiological facts. Taken together, they convince us that the phronema is undeveloped in the new-born infant; and so we can no more speak in this case of a "seat of the soul" than of a "human spirit" as a centre of thought, knowledge, and consciousness. Hence the destruction of abnormal new-born infants--as the Spartans practised it, for instance, in selecting the bravest--cannot rationally be classed as "murder," as is done in even modern legal works. We ought rather to look upon it as a practice of advantage both to the infants destroyed and to the community. As the whole course of embryology is, according to our biogenetic law, an abbreviated repetition of the history of the race, we must say the same of psychogenesis, or the development of the "soul" and its organ--the phronema.