Psychic Contagion. Direct contagion of the tendency to lie seems more than likely to take place, at least during the more plastic periods of life. It may be that this only develops when there is some sort of predisposition to instability; our related findings on defective heredity would seem to indicate the fact. It should be noted that in 5 instances out of our 19 mentally normal (Cases 2, 4, 6, 8, 20) some other member of the household, we learned from reliable sources, was known as a chronic prevaricator. Mental Conflicts. The fact that several of our cases started lying from the time when there occurred some experience accompanied by a deep emotional context, and that this experience and the emotion was repressed, seems to point clearly to the part which repressed mental life may play in the genesis. That as children they kept to themselves secrets of grave import and dwelled long on them, shows in a large number of our cases. Anything deeply upsetting, such as the discovery of the facts of sex life or questions about family relationships, are the incidents which cause the trouble. For students of modern psychology nothing more need be said on this point--the concrete issues are perceivable in the case histories. Adolescence. Quite apart from the age of onset, we may consider the physical and psychical instabilities of adolescence as effective causes of pathological lying. Of course it is equally true that many other tendencies to peculiarity are accentuated at this period. It has been suggested that cases which have their origin largely in the unstable reactions of adolescence have much the better prognosis, but it seems that not enough evidence has been accumulated as yet to justify us in this conclusion, which, we acknowledge, may prove to be true. Irritative Conditions. In the same way the various types of irritative conditions, physical and mental, may be considered as exciting moments. Individuals with a tendency to pathological lying will no doubt show aggravation of the phenomenon at periods of particular stress. We have heard it suggested in several cases by relatives that the menstrual period, for instance, brings about an access of tendency to prevarication. We would grant the point without conceding this exciting factor to be a fundamental cause. (Case 21, we may say again, illustrates a special fact.) The periodicity which Stemmermann makes much of may merely mean succumbing during a period of physiologic stress. Social stress also may be met by pathological lying, in the same way that the individual who finds himself in a tight place may attempt to get out of it by running away. We have already spoken of the likeness of social and physical stress as showing when the weak individual is brought to bay. That pathological lying does not run an even course, but shows remarkable fluctuations with powerful exacerbations, is undoubtedly to be explained by changes of inner and outer stress.