lations as found in the child, in the
woman, and in the castrated male. In none of the three cases can we
speak of an accumulation of sexual products in the same sense as in the
man, which naturally renders difficult the general application of this
scheme; still it may be admitted without any further ado that ways can
be found to justify the subordination of even these cases. Nevertheless
one should be cautious about burdening the factor of accumulation of
sexual products with actions which it seems incapable of supporting.

*Overestimation of the Internal Genitals.*--That sexual excitement can
be independent to a considerable extent of the production of sexual
substance seems to be shown by observations on castrated males, in whom
the libido sometimes escapes the injury caused by the operation,
although the opposite behavior, which is really the motive for the
operation, is usually the rule. It is therefore not at all surprising,
as C. Rieger puts it, that the loss of the male germ glands in maturer
age should exert no new influence on the psychic life of the individual.
The germ glands are really not the sexuality, and the experience with
castrated males only verifies what we had long before learned from the
removal of the ovaries, namely that it is impossible to do away with the
sexual character by removing the germ glands. To be sure, castration
performed at a tender age, before puberty, comes nearer to this aim, but
it would seem in this case that besides the loss of the sexual glands we
must also consider the inhibition of development and other factors
which are connected with that loss.

*Chemical Theories.*--The truth remains, however, that we are unable to
give any information about the nature of the sexual excitement for the
reason that we do not know with what organ or organs sexuality is
connected, since we have seen that the sexual glands have been
overestimated in this significance. Since surprising discoveries have
taught us the important role of the thyroid gland in sexuality, we may
assume that the knowledge of the essential factors of sexuality are
still withheld from us. One who feels the need of filling up the large
gap in our knowledge with a preliminary assumption may formulate for
himself the following theory based on the active substances found in the
thyroid. Through the appropriate excitement of erogenous zones, as well
as through other conditions under which sexual excitement originates, a
ma