Christophorus Christum, sed Christus sustulit orbem: Constiterit pedibus dic ubi Christophorus? Now that I once more approach the riddle of suggestion after having kept away from it for some thirty years, I find there is no change in the situation. To this statement I can discover only a single exception, which I need not mention, since it is one which bears witness to the influence of psycho-analysis. I notice that particular efforts are being made to formulate the concept of suggestion correctly, that is, to fix the conventional use of the name.[24] And this is by no means superfluous, for the word is acquiring a more and more extended use and a looser and looser meaning, and will soon come to designate any sort of influence whatever, just as in English, where 'to suggest' and 'suggestion' correspond to our _nahelegen_ and _Anregung_. But there has been no explanation of the nature of suggestion, that is, of the conditions under which influence without adequate logical foundation takes place. I should not avoid the task of supporting this statement by an analysis of the literature of the last thirty years, if I were not aware that an exhaustive inquiry is being undertaken close at hand which has in view the fulfilment of this very task. Instead of this I shall make an attempt at using the concept of _libido_ for the purpose of throwing light upon Group Psychology, a concept which has done us such good service in the study of psycho-neuroses. Libido is an expression taken from the theory of the emotions. We call by that name the energy (regarded as a quantitative magnitude, though not at present actually mensurable) of those instincts which have to do with all that may be comprised under the word 'love'. The nucleus of what we mean by love naturally consists (and this is what is commonly called love, and what the poets sing of) in sexual love with sexual union as its aim. But we do not separate from this--what in any case has a share in the name 'love'--on the one hand, self-love, and on the other, love for parents and children, friendship and love for humanity in general, and also devotion to concrete objects and to abstract ideas. Our justification lies in the fact that psycho-analytic research has taught us that all these tendencies are an expression of the same instinctive activities; in relations between the sexes these instincts force their way towards sexual union, but in other circumstances they are diverted from this aim or are prevented from reaching it, though always preserving enough of their original nature to keep their identity recognizable (as in such features as the longing for proximity, and self-sacrifice).