terial which is universally distributed in the organism becomes
disintegrated, the decomposing products of which supply a specific
stimulus to the organs of reproduction or to the spinal center connected
with them. Such a transformation of a toxic stimulus in a particular
organic stimulus we are already familiar with from other toxic products
introduced into the body from without. To treat, if only hypothetically,
the complexities of the pure toxic and the physiologic stimulations
which result in the sexual processes is not now our appropriate task. To
be sure, I attach no value to this special assumption and I shall be
quite ready to give it up in favor of another, provided its original
character, the emphasis on the sexual chemism, were preserved. For this
apparently arbitrary statement is supported by a fact which, though
little heeded, is most noteworthy. The neuroses which can be traced only
to disturbances of the sexual life show the greatest clinical
resemblance to the phenomena of intoxication and abstinence which result
from the habitual introduction of pleasure-producing poisonous
substances (alkaloids.)

THE THEORY OF THE LIBIDO

These assumptions concerning the chemical basis of the sexual excitement
are in full accord with the auxiliary conception which we formed for the
purpose of mastering the psychic manifestations of the sexual life. We
have determined the concept of _libido_ as that of a force of variable
quantity which has the capacity of measuring processes and
transformations in the spheres of sexual excitement. This libido we
distinguished from the energy which is to be generally adjudged to the
psychic processes with reference to its special origin and thus we
attribute to it also a qualitative character. In separating libidinous
from other psychic energy we give expression to the assumption that the
sexual processes of the organism are differentiated from the nutritional
processes through a special chemism. The analyses of perversions and
psychoneuroses have taught us that this sexual excitement is furnished
not only from the so-called sexual parts alone but from all organs of
the body. We thus formulate for ourselves the concept of a
libido-quantum whose psychic representative we designate as the
ego-libido; the production, increase, distribution and displacement of
this ego-libido will offer the possible explanation for the observed
psycho-sexual phenomena.

But this ego-libido becomes con