Losing and mislaying objects is of especial interest on account of the numerous meanings it may have, and the multiplicity of the tendencies in the service of which these errors may be employed. What is common to all the cases is the wish to lose something; what varies in them is the reason for the wish and the aim of it. One loses something if it has become damaged; if one has an impulse to replace it with a better; if one has ceased to care for it; if it came from someone with whom unpleasantness has arisen; or if it was acquired in circumstances that one no longer wishes to think of. Letting things fall, spoiling, or breaking things, serves the same tendency. In social life it is said that unwelcome and illegitimate children are found to be far more often weakly than those conceived in happier circumstances. This result does not imply that the crude methods of the so-called baby-farmer have been employed; some degree of carelessness in the supervision of the child should be quite enough. The preservation, or otherwise, of objects may well follow the same lines as that of children. Then too it may happen that a thing will become destined to be lost without its having shed any of its value—that is, when there is an impulse to sacrifice something to fate in order to avert some other dreaded loss. According to the findings of analysis, such conjurings of fate are still very common among us, so that our losses are often voluntary sacrifices. Losing may equally well serve the impulses of spite or of self-punishment; in short, the more remote forms of motivation behind the impulse to do away with something by losing cannot easily be exhausted. Mistaking of objects, or erroneous performance of actions, like other errors, is often made use of to fulfil a wish which should be denied; the intention masquerades as a lucky chance. Thus, as once happened to one of our friends, one has to take a train, most unwillingly, in order to pay a visit in the suburbs and then, in changing trains at a connection, one gets by mistake into one which is returning to town; or, on a journey one would greatly like to make a halt at some stopping-place, which cannot be done owing to fixed engagements elsewhere, whereupon one mistakes or misses the connection, so that the desired delay is forced upon one. Or, as happened to one of my patients whom I had forbidden to telephone to the lady he was in love with, he “by mistake” and “thoughtlessly” gave the wrong number when he meant to telephone to me, so that he was suddenly connected with her. The following account by an engineer is a pretty example of the conditions under which damage to material objects may be done, and also demonstrates the practical significance of directly faulty actions.