Associations of this character have been the subject matter of very enlightening experimental investigations, which have played a noteworthy role in the history of psychoanalysis. The Wundt school proposed the so-called association-experiment, wherein the subject is given the task of answering in the quickest possible time, with any desired reaction, to a given stimulus-word. It is then possible to study the interval of time that elapses between the stimulus and the reaction, the nature of the answer given as reaction, the possible mistake in a subsequent repetition of the same attempt, and similar matters. The Zurich School under the leadership of Bleuler and Jung, gave the explanation of the reactions following the association-experiment, by asking the subject to explain a given reaction by means of further associations, in the cases where there was anything extraordinary in the reaction. It then became apparent that these extraordinary reactions were most sharply determined by the complexes of the subject. In this matter Bleuler and Jung built the first bridge from experimental psychology to psychoanalysis. Thus instructed, you will be able to say, "We recognize now that free associations are predetermined, not voluntary, as we had believed. We admit this also as regards the associations connected with the elements of the dream, but that is not what we are concerned with. You maintain that the associations to the dream element are determined by the unknown psychic background of this very element. We do not think that this is a proven fact. We expect, to be sure, that the association to the dream element will clearly show itself through one of the complexes of the dreamer, but what good is that to us? That does not lead us to understand the dream, but rather, as in the case of the association-experiment, to a knowledge of the so-called complexes. What have these to do with the dream?" You are right, but you overlook one point, in fact, the very point because of which I did not choose the association-experiment as the starting point for this exposition. In this experiment the one determinate of the reaction, viz., the stimulus word, is voluntarily chosen. The reaction is then an intermediary between this stimulus word and the recently aroused complex of the subject. In the dream the stimulus word is replaced by something that itself has its origin in the psychic life of the dreamer, in sources unknown to him, hence very likely itself a product of the complex. It is not an altogether fantastic hypothesis, then, that the more remote associations, even those that are connected with the dream element, are determined by no other complex than the one which determines the dream element itself, and will lead to the disclosure of the complex.