I wish to avoid making reservations later on about the universal applicability of these statements, and therefore I will ask you to notice that all I have just been saying about repression, symptom-formation and symptom-interpretation has been obtained from the study of three types of neurosis, and for the present is only applicable to these three types—namely, _anxiety-hysteria_, _conversion-hysteria_, and _the obsessional neurosis_. These three disorders, which we are accustomed to combine together in a group as the TRANSFERENCE NEUROSES, constitute the field open to psycho-analytic therapy. The other neuroses have been far less closely studied psycho-analytically; in one group of them the impossibility of therapeutic influence has no doubt been one reason for this neglect. You must not forget that psycho-analysis is still a very young science, that much time and trouble are required for the study of it, and that not so very long ago there was only one man practising it: yet we are approaching from all directions to a nearer comprehension of these other conditions which are not transference neuroses. I hope I shall still be able to tell you of the developments that our hypotheses and conclusions have undergone in the course of adaptation to this new material, and to show you that these further studies have not yielded contradictions but have led to a higher degree of unification in our knowledge. Everything that has been said, then, applies only to the three transference neuroses and I will now add another piece of information which throws further light upon the significance of the symptoms. A comparative examination of the situations out of which the disease arose yields the following result, which may be reduced to a formula—namely, that these persons have fallen ill owing to some kind of PRIVATION which they suffer when reality withholds from them gratification of their sexual wishes. You will perceive how beautifully these two conclusions supplement one another. The symptoms are now explicable as substitute-gratifications for desires which are unsatisfied in life.