more common
among females.[302]

There appears to be no limit to the age at which spontaneous masturbation
may begin to appear. I have already referred to the practice of
thigh-rubbing in infants under one year of age. J.P. West has reported in
detail 3 cases of masturbation in very early childhood--2 in girls, 1 in a
boy--in which the practice had been acquired spontaneously, and could only
be traced to some source of irritation in pressure from clothing,
etc.[303] Probably there is often in such cases some hereditary lack of
nervous stability. Block has recorded the case of a girl--very bright for
her age, though excessively shy and taciturn--who began masturbating
spontaneously at the age of two; in this case the mother had masturbated
all her life, even continuing the practice after marriage, and, though she
succeeded in refraining during pregnancy, her thoughts still dwelt upon
it, while the maternal grandmother had died in an asylum from
"masturbatory insanity."

Freud considers that auto-erotic manifestations are common in infancy, and
that the rhythmic function of any sensitive spot, primarily the lips, may
easily pass into masturbation. He regards the infantile manifestations of
which thumb-sucking is the most familiar example (Luedeln or Lutschen in
German) as auto-erotic, the germ arising in sucking the breasts since the
lips are an erogenous zone which may easily be excited by the warm stream
of milk. But this only occurs, he points out, in subjects in whom the
sensitivity of the lip zone is heightened and especially in those who at a
later age are liable to become hysterical.[304] Shuttleworth also points
out that the mere fidgetiness of a neurotic infant, even when only a few
months old, sometimes leads to the spontaneous and accidental discovery of
pleasurable sexual sensations, which for a time appease the restlessness
of nervous instability, though a vicious circle is thus established. He
has found that, especially among quite young girls of neurotic heredity,
self-induced excitement, often in the form of thigh-friction, is more
common than is usually supposed.[305]

Normally there appears to be a varying aptitude to experience the sexual
organism, or any voluptuous sensations before puberty. I find, on
eliciting the recollections of normal persons, that in some cases there
have been voluptuous sensations from casual contact with the sexual organs
at a very early age; in other cases there has been occ