occurrence of dark brown stripes on the neck, withers and legs of ordinary colts is not uncommon, some cases of which have exhibited more zebra-like markings than those of the colts from Lord Morton's mare. It seems much more probable, therefore, that the alleged instances are merely cases of ordinary reversion to the striped ancestral color pattern which probably characterized the wild progenitors of the domesticated horse. Various experiments on guinea-pigs, horses, mice and other forms, especially devised to test out this alleged after-influence of an earlier sire, have all proved negative and the general belief of the biologist to-day is that telegony is a myth. =Prenatal Influences Apart from Heredity.--=In discussing the problems of heredity it is necessary to consider also the possibilities of external influences apart from lineage which may affect offspring through either parent. Although modifications derived directly by the parent, and prenatal influences in general, are of extremely doubtful value as of permanent inheritable significance, nevertheless they must be reckoned with in any inventory of a child's endowment at birth. Impaired vitality on the part of the mother, bad nutrition and physical vicissitudes of various kinds all enter as factors in the birthright of the child, who, moreover, may bear in its veins slumbering poisons from some progenitor who has handed on blood taints not properly attributable to heredity. Of such importance is this kind of influence to the welfare of the immediate child that it will be necessary to discuss it in considerable detail in a later chapter. =Parent Body and Germ Not Identical.--=Inasmuch as each new individual appears to arise from material derived from its parent, taking the evidence at its face value one might suppose that any peculiarity of organization called forth in the living substance of the parent would naturally be repeated in the offspring, but a closer study of the developing organism from its first inception to maturity shows this to be probably a wrong conclusion. The parent-body and the reproductive substance contained in that body are by no means identical. It becomes an important question to decide, in fact, how much effect, if any, either permanent or temporary, the parent-body really has on the germ. A given fertile germ (Fig. 2, p. 13) gives rise by a succession of divisions to a body which we call the individual, but such a germ also gives rise to a series of new germ-cells which reside in that individual, and it is these germ-cells, not something derived from the body, that pass on the determiners of distinguishing features or qualities from generation to generation. It is only by grasping the significance of this fact that we can understand how in certain cases a totally different set of characters may appear in an offspring than those manifested in either parent.