nics. Chicago, 1912,
pp. 164, 254-5.

15. Conklin, E.G. Share of Egg and Sperm in Heredity. Proc. Nat. Acad.
of Sc., Feb., 1917.

16. Goodale, H.D. A Feminized Cockerel. Jour. Exp. Zool. Vol. 20,
pp. 421-8.

17. Ward, Lester F. Pure Sociology. N.Y., 1903, pp. 322f.

18. Ellis, Havelock. Man and Woman, 4th Ed. London, 1904. Ch. XVI.

19. Hall, G. Stanley. Adolescence. N.Y., 1907. Vol. II, pp. 561-2.

20. Morgan, T.H. Heredity and Sex. N.Y., 1913, pp. 155f.

21. Lillie, F.R. Theory of the Free Martin. Science, n.s., Vol. XLIII,
pp. 611-13.

22. Neugebauer, F.L. Hermaphrodismus, Leipzig, 1908.

23. Vincent, S. Internal Secretions and the Ductless Glands. London,
1912, p. 69.

24. Marshall, F.H. Physiology of Reproduction. London, 1910, p. 314.

CHAPTER III

SEX AND SEX DIFFERENCES AS QUANTITATIVE

Intersexes in moths; Bird intersexes; Higher metabolism of males;
Quantitative difference between sex factors; Old ideas of
intersexuality; Modern surgery and human intersexes; Quantitative theory
a Mendelian explanation; Peculiar complication in the case of man;
Chemical life cycles of the sexes; Functional-reproductive period and
the sex problem; Relative significance of physiological sex differences.

Crossing European and Japanese gypsy moths, Goldschmidt [1,2,3,4]
noticed that the sex types secured were not pure--i.e., that certain
crosses produced females which bore a distinctly greater resemblance to
the male type than others, and _vice versa_. One of these hybrids of
"intersexes," as he calls them, would always possess some female and
some male sexual characters. He found that he could separate the males
and females, respectively, into seven distinct grades with respect to
their modification toward the opposite-sex type, and could produce any
one of these grades at will by breeding.

For example, the seven grades of females were roughly as follows:
(1) Pure females; (2) Females with feathered antennae like males and
producing fewer than the normal number of eggs; (3) Appearance of the
brown (male) patches on the white female wings; ripe eggs in abdomen,
but only hairs in the egg-sponge laid; instincts still female;
(4) Instincts less female; whole sections of wings with male colouration,
interspersed with cuneiform female sectors; abdomen smaller, males less
attracted; reproduction impossible; (5) Male colouration over almost the
entire wing; abdomen almost male, with few ripe eggs; instincts
i