In one group of cases by a very safe and simple method, by the same method, that is, by which we establish the tendency that is interfered with. We enquire of the speaker, who tells us then and there; after making the slip he restores the word he originally intended. “O, it may _stad_—no, it may _take_ another month.” Well, the interfering tendency may be likewise supplied by him. We say, “Now why did you first say stad?” He replies, “I meant to say it was a sad business”; and in the other case in which “refilled” was said, the speaker informs you that he first meant to say it was a filthy business, but controlled himself and substituted another expression. The discovery of the disturbing tendency is here as definitely established as that of the disturbed tendency. It is not without intention that I have selected as examples cases which owe neither their origin nor their explanation to me or to any supporter of mine. Still, in both these cases, a certain intervention was necessary in order to produce the explanation. One had to ask the speaker why he made the slip, what explanation he could give. Without that he might have passed it by without seeking to explain it. Being asked, however, he gave as his answer the first idea that occurred to him. And see now, this little intervention and the result of it constitute already a psycho-analysis, a prototype of every psycho-analytic investigation that we may undertake further. Now, should I be too suspicious if I were to surmise that, at the very moment at which psycho-analysis begins to dawn upon you, a resistance to it instantly raises itself within your mind? Are you not eager to object that information supplied by the person enquired of, who committed the slip, is not completely reliable evidence. He naturally wishes, you think, to meet your request to explain his slip, and so he says the first thing that he can think of, if it will do at all. There is no proof that that is actually how the slip arose. It may have been so, but it may just as well have been otherwise. Something else also might have occurred to him that would have met the case as well or even better.