It is not here asserted, as I would carefully point out, that an inverted sexual instinct, or organ for such instinct, is developed in early embryonic life; such a notion is rightly rejected as absurd.  What we may reasonably regard as formed at an early stage of development is strictly a predisposition; that is to say, such a modification of the organism that it becomes more adapted than the normal or average organism to experience sexual attraction to the same sex.  The sexual invert may thus be roughly compared to the congenital idiot, to the instinctive criminal, to the man of genius, who are all not strictly concordant with the usual biological variation (because this is of a less subtle character), but who become somewhat more intelligible to us if we bear in mind their affinity to variations.  Symonds compared inversion to color-blindness; and such a comparison is reasonable.  Just as the ordinary color-blind person is congenitally insensitive to those red-green rays which are precisely the most impressive to the normal eye, and gives an extended value to the other colors,—­finding that blood is the same color as grass, and a florid complexion blue as the sky,—­so the invert fails to see emotional values patent to normal persons, transferring those values to emotional associations which, for the rest of the world, are utterly distinct.  Or we may compare inversion to such a phenomenon as color-hearing, in which there is not so much defect as an abnormality of nervous tracks producing new and involuntary combinations.  Just as the color-hearer instinctively associates colors with sounds, like the young Japanese lady who remarked when listening to singing, “That boy’s voice is red!” so the invert has his sexual sensations brought into relationship with objects that are normally without sexual appeal.[237] And inversion, like color-hearing is found more commonly in young subjects, tending to become less marked, or to die out, after puberty.  Color-hearing, while an abnormal phenomenon, it must be added, cannot be called a diseased condition, and it is probably much less frequently associated with other abnormal or degenerative stigmata than is inversion; there is often a congenital element, shown by the tendency to hereditary transmission, while the associations are developed in very early life, and are too regular to be the simple result of suggestion.[238]

All such organic variations are abnormalities.  It is important that we should have a clear idea as to what an abnormality is.  Many people imagine that what is abnormal is necessarily diseased.  That is not the case, unless we give the word disease an inconveniently and illegitimately wide extension.  It is both inconvenient and inexact to speak of color-blindness, criminality, and genius as diseases in the same sense as we speak of scarlet fever or tuberculosis or general paralysis as diseases.  Every congenital abnormality is doubtless due to a peculiarity in the sperm or