Hypnosis would solve the riddle of the libidinal constitution of groups for us straight away, if it were not that it itself exhibits some features which are not met by the rational explanation we have hitherto given of it as a state of being in love with the directly sexual tendencies excluded. There is still a great deal in it which we must recognise as unexplained and mystical. It contains an additional element of paralysis derived from the relation between someone with superior power and someone who is without power and helpless--which may afford a transition to the hypnosis of terror which occurs in animals. The manner in which it is produced and its relationship to sleep are not clear; and the puzzling way in which some people are subject to it, while others resist it completely, points to some factor still unknown which is realised in it and which perhaps alone makes possible the purity of the attitudes of the libido which it exhibits. It is noticeable that, even when there is complete suggestive compliance in other respects, the moral conscience of the person hypnotized may show resistance. But this may be due to the fact that in hypnosis as it is usually practised some knowledge may be retained that what is happening is only a game, an untrue reproduction of another situation of far more importance to life. But after the preceding discussions we are quite in a position to give the formula for the libidinal constitution of groups: or at least of such groups as we have hitherto considered, namely, those that have a leader and have not been able by means of too much 'organisation' to acquire secondarily the characteristics of an individual. _A primary group of this kind is a number of individuals who have substituted one and the same object for their ego ideal and have consequently identified themselves with one another in their ego._ This condition admits of graphic representation: [Illustration] IX THE HERD INSTINCT We cannot for long enjoy the illusion that we have solved the riddle of the group with this formula. It is impossible to escape the immediate and disturbing recollection that all we have really done has been to shift the question on to the riddle of hypnosis, about which so many points have yet to be cleared up. And now another objection shows us our further path.