The conjecture which leads furthest, however, is that—and here we come back to the remarks in the footnote on p. 66—the whole of sexuality and not merely anal erotism is threatened with falling a victim to the organic repression consequent upon man’s adoption of the erect posture and the lowering in value of the sense of smell; so that since that time the sexual function has been associated with a resistance not susceptible of further explanation, which puts obstacles in the way of full satisfaction and forces it away from its sexual aim towards sublimations and displacements of libido. I am aware that Bleuler (in ‘Der Sexualwiderstand’, _Jahrbuch für psychoanalytische und psychopathologische Forschungen_, Bd. v., 1913) once pointed out the existence of a fundamental tendency of this kind towards rejecting sexual life. All neurotics, and many others too, take exception to the fact that ‘inter urinas et faeces nascimur’. The genitals, too, excite the olfactory sense strongly in a way that many people cannot tolerate and which spoils sexual intercourse for them. Thus we should find, as the deepest root of the sexual repression that marches with culture, the organic defence of the new form of life that began with the erect posture against the earliest type of animal existence—a result of scientific researches that coincides in a curious way with often expressed vulgar prejudices. At the present time, nevertheless, these results are but unconfirmed possibilities, not yet scientifically substantiated. Nor should we forget that, in spite of the undeniable diminution in the importance of olfactory stimuli, there exist even in Europe races who prize highly as aphrodisiacs the strong genital odours so objectionable to us and who will not renounce them. (Cf. the reports of folkloristic information obtained by Iwan Bloch’s ‘Questionnaire’, appearing under the title of ‘Über den Geruchssinn in der vita sexualis’ in various volumes of Friedrich S. Krauss’ _Anthropophyteia_.) V Psycho-analytic work has shown that these frustrations in respect of sexual life are especially unendurable to the so-called neurotics among us. These persons manufacture substitute-gratifications for themselves in their symptoms, which, however, are either painful in themselves or become the cause of suffering owing to the difficulties they create with the person’s environment and society at large. It is easy to understand the latter fact, but the former presents us with a new problem. But culture demands other sacrifices besides that of sexual gratifications.