There is an unmistakable social factor at work in the impulse of civilization towards cleanliness, which has been subsequently justified by considerations of hygiene but had nevertheless found expression before they were appreciated. The impulse towards cleanliness originates in the striving to get rid of excretions which have become unpleasant to the sense-perceptions. We know that things are different in the nursery. Excreta arouse no aversion in children; they seem precious to them, as being parts of their own bodies which have been detached from them. The training of children is very energetic in this particular; its object is to expedite the development that lies ahead of them, according to which the excreta are to become worthless, disgusting, horrible and despicable to them. Such a reversal of values would be almost impossible to bring about, were it not that these substances expelled from the body are destined by their strong odours to share the fate that overtook the olfactory stimuli after man had erected himself from the ground. Anal erotism, therefore, is from the first subjected to the ‘organic repression’ which opened up the way to culture. The social factor which has been active in the further modifications of anal erotism comes into play with the fact that in spite of all man’s evolutionary progress the smell of his own excretions is scarcely disagreeable to him yet, but so far only that of the evacuations of others. The man who is not clean, _i.e._ who does not eliminate his excretions, therefore offends others, shows no consideration for them—a fact which is exemplified in the commonest and most forcible terms of abuse. It would be incomprehensible, too, that man should use as an abusive epithet the name of his most faithful friend in the animal world, if dogs did not incur the contempt of men through two of their characteristics, _i.e._ that they are creatures of smell and have no horror of excrement, and, secondly, that they are not ashamed of their sexual functions. [14] There is a short story, which I valued long ago, by a highly sensitive writer, the Englishman, John Galsworthy, who to-day enjoys general recognition; it is called ‘The Apple Tree’. It shows in a very moving and forcible way how there is no longer any place in present-day civilized life for a simple natural love between two human beings.