This genetic constitution is modified by the cytoplasm, the supporting part of the cell which is its first environment, and further by the entire embryonic environment. Any changes that take place after the launching of this cell, whether before or after birth, are regarded as environmental. In the embryonic life, this germinating cell develops by processes of cell division and specialization into the complete human organism ready to function more or less immediately after birth. This heritage has fabulous resources in the form of possible facilities for future development. As nature was prolific in the storing and transmission of countless hereditary characters in the genetic constitution, so the equipment of the child at birth is astonishingly prolific in the provision it makes for diversified development of the individual. Development from this stage on must, therefore, of necessity take place through a process of selection and specialization in which certain characters are given right of way and many are subordinated or inhibited by conflicting interests, but the great mass remain relatively latent or dormant. We may assume that superior musical talent is determined in large part by superior musical heredity, and that inferior musical talent or lack of talent may be determined in large part by a correspondingly defective heredity. The science of heredity in the strictest sense focuses upon the study of the identification and organization of the genes in relation to the determination of characters which shall appear in the genetic constitution and determine future structures and functions of the individual. When the geneticist deals with specific anatomical structures, this relationship is traceable with comparative ease; but when he comes to deal with more or less complicated physiological or mental functions, the tracing of this relationship becomes rather baffling on account of the complexity of the final product. Turning then to the issues involved in the interpretation of musical inheritance, we must face certain theoretical assumptions. One of them is that a scientific study of musical heredity cannot be pursued on the assumption that mind and body are two distinct entities, each inherited independently. Nor can we hold the old doctrine of psychophysical parallelism. All human genetics proceeds on the assumption that the human individual is one psychophysical organism. Our musical experience, observation and measurement will therefore represent views from the mental side; our organic studies may be views of the same things from the physical side.