“Who last grasped the tuning-fork?” was the question which immediately flashed through my mind. It happened that only a few days ago an idiotic child, whose attention to sensory impressions I was testing, had been so fascinated by the tuning-fork that I found it difficult to tear it away from him. Could it mean, therefore, that I was an idiot? To be sure, so it would seem, as the next thought which associated itself with the hammer was _chamer_ (Hebrew for “ass”). But what was the meaning of this abusive language? We must here inquire into the situation. I hurried to a consultation at a place on the Western railroad to see a patient who, according to the anamnesis which I received by letter, had fallen from a balcony some months before, and since then had been unable to walk. The physician who invited me wrote that he was still unable to say whether he was dealing with a spinal injury or traumatic neurosis--hysteria. That was what I was to decide. This could therefore be a reminder to be particularly careful in this delicate differential diagnosis. As it is, my colleagues think that hysteria is diagnosed far too carelessly where more serious matters are concerned. But the abuse is not yet justified. Yes, the next association was that the small railroad station is the same place in which, some years previous, I saw a young man who, after a certain emotional experience, could not walk properly. At that time I diagnosed his malady as hysteria, and later put him under psychic treatment; but it afterward turned out that my diagnosis was neither incorrect nor correct. A large number of the patient’s symptoms were hysterical, and they promptly disappeared in the course of treatment. But back of these there was a visible remnant that could not be reached by therapy, and could be referred only to a multiple sclerosis. Those who saw the patient after me had no difficulty in recognizing the organic affection. I could scarcely have acted or judged differently, still the impression was that of a serious mistake; the promise of a cure which I had given him could naturally not be kept. The mistake in grasping the tuning-fork instead of the hammer could therefore be translated into the following words: “You fool, you ass, get yourself together this time, and be careful not to diagnose again a case of hysteria where there is an incurable disease, as you did in this place years ago in the case of the poor man!” And fortunately for this little analysis, even if unfortunately for my mood, this same man, now having a very spastic gait, had been to my office a few days before, one day after the examination of the idiotic child. We observe that this time it is the voice of self-criticism which makes itself perceptible through the mistake in grasping. The erroneously carried-out action is specially suited to express self-reproach. The present mistake attempts to represent the mistake which was committed elsewhere.