cific sexual inversion.[130]

It may now be said to be recognized by all authorities, even by Freud who
emphasizes a special psychological mechanism by which homosexuality may
become established, that a congenital predisposition as well as an
acquired tendency is necessary to constitute true inversion, apparent
exceptions being too few to carry much weight. Krafft-Ebing, Naecke, Iwan
Bloch, who at one time believed in the possibility of acquired inversion,
all finally abandoned that view, and even Schrenck-Notzing, a vigorous
champion of the doctrine of acquired inversion twenty years ago, admits
the necessity of a favoring predisposition, an admission which renders the
distinction between innate and acquired an unimportant, if not a merely
verbal, distinction.[131] Supposing, indeed, that we are prepared to admit
that true inversion may be purely acquired the decision in any particular
case must be extremely difficult, and I have found very few cases which,
even with imperfect knowledge, could fairly so be termed.

Even the cases (to which Schopenhauer long since referred) in which
inversion is only established late in life, are no longer regarded as
constituting a difficulty in accepting the doctrine of the congenital
nature of inversion; in such cases the inversion is merely retarded. The
conception of retarded inversion,--that is to say a latent congenital
inversion becoming manifest at a late period in life,--was first brought
forward by Thoinot in 1898 in his _Attentats aux Moeurs_, in order to
supersede the unsatisfactory conception, as he considered it to be, of
acquired inversion. Thoinot regarded retarded inversion as relatively rare
and of no great importance but more accessible to therapeutic measures.
Three years later, Krafft-Ebing, toward the close of his life, adopted the
same conception; the cases to which he applied it were all, he considered,
of bisexual disposition and usually, also, marked by sexual hyperesthesia.
This way of looking at the matter was speedily championed by Naecke and may
now be said to be widely accepted.[132]

Moll, earlier than Thoinot, had pointed out that it is difficult to
believe that homosexuality in late life can ever be produced without at
least some inborn weakness of the heterosexual impulse, and that we must
not deny the possibility of heredity even when homosexuality appears at
the age of 50 or 60.[133]

Moll believes it is very doubtful whether heterosexual sati