secretions of the genital glands. Examples of these are the beards in men, the luxuriant growth of hair in women, the development of the mammary glands, the character of the voice. As a convenient mode of treatment, and for practical rather than theoretical reasons, certain inherited characters, such as the development of muscular strength or of mental obstinacy may be reckoned as tertiary sexual characters. Under the designation "quaternary sexual characters" may be placed such accessories as relative social position, difference in habit, mode of livelihood, the smoking and drinking habit in man, and the domestic duties of women. All these characters possess a potent and direct sexual influence, and in my opinion often may be reckoned with the tertiary characters or even with the secondary. This classification of sexual characters must not be taken as implying a definite nite chain of sequence, nor must it be assumed that the mental sexual characters either determine the bodily characters or are determined by them in some causal nexus. The classification relates only to the strength of the exciting influence on the other sex, to the order in time in which this influence is exerted, and to the degree of certainty with which the extent of the influence may be predicted.
Study of secondary sexual characters is bound up with consideration of the effect of internal secretions of the genital glands on general metabolism. The relation of this influence or its absence (as in the case of artificially castrated animals) has been traced out in the degree of development of the secondary characters. The internal secretions, however, undoubtedly have an influence on all the cells of the body. This is clearly shown by the changes which occur at puberty in all parts of the body, and not only in the seats of the secondary sexual characters. As a matter of fact, the internal secretions of all the glands must be regarded as affecting all the tissues.
The internal secretions of the genital glands must be regarded as completing the sexuality of the individual. Every cell must be considered as possessing an original sexuality, to which the influence of the internal secretion in
