so
intimately connected as to form two distinct stages in the same process: a
first stage, in which--usually under the parallel influence of internal
and external stimuli--images, desires, and ideals grow up within the mind,
while the organism generally is charged with energy and the sexual
apparatus congested with blood; and a second stage, in which the sexual
apparatus is discharged amid profound sexual excitement, followed by deep
organic relief. By the first process is constituted the tension which the
second process relieves. It seems best to call the first impulse the
_process of tumescence_; the second the _process of detumescence_.[60] The
first, taking on usually a more active form in the male, has the double
object of bringing the male himself into the condition in which discharge
becomes imperative, and at the same time arousing in the female a similar
ardent state of emotional excitement and sexual turgescence. The second
process has the object, directly, of discharging the tension thus produced
and, indirectly, of effecting the act by which the race is propagated.

It seems to me that this is at present the most satisfactory way in which
we can attempt to define the sexual impulse.

FOOTNOTES:

[1] C. Lloyd Morgan, "Instinct and Intelligence in Animals," _Nature_,
February 3, 1898.

[2] _Essais_, livre iii, ch. v.

[3] Fere, "La Predisposition dans l'etiologie des perversions sexuelles,"
_Revue de medecine_, 1898. In his more recent work on the evolution and
dissolution of the sexual instinct Fere perhaps slightly modified his
position by stating that "the sexual appetite is, above all, a general
need of the organism based on a sensation of fullness, a sort of need of
evacuation," _L'Instinct sexuel_, 1899, p. 6. Loewenfeld (_Ueber die
Sexuelle Konstitution_, p. 30) gives a qualified acceptance to the
excretory theory, as also Rohleder (_Die Zeugung beim Menschen_, p. 25).

[4] Goltz, _Centralblatt fuer die med. Wissenschaften_, 1865, No. 19, and
1866, No. 18; also _Beitraege zur Lehre von den Funktionen des Frosches_,
Berlin, 1869, p. 20.

[5] J. Tarchanoff, "Zur Physiologie des Geschlechtsapparatus des
Frosches," _Archiv fuer die Gesammte Physiologie_, 1887, vol. xl, p. 330.

[6] E. Steinach, "Untersuchungen zur vergleichenden Physiologie der
maennlicher Geschlechtsorgane insbesondere der accessorischen
Geschlechtsdruesen," _Archiv fuer die Gesammte Physiologie_, vol. lvi,
1894, pp. 304-338.