of whom I obtained information, but did not study, there were three cases, an uncle, a mother, and a brother. In another family there were two boys, both Jumpers. Here, then, were fourteen cases in four families. By the study of these cases, it was possible to trace the malady back at least half a century.
Endemic and contagious.—Jumping seems to be endemic, confined mainly to the north woods of Maine and to those of French descent, and is psycho-contagious—that is, can be caught by personal contact, like chorea and hysteria.
Shortly after I began these researches, I found in a copy of the London "Medical Record" brief reference to precisely similar phenomena on the other side of the globe, among the Malays. The notice was very brief, indeed, but it was sufficient to show that there was no difference in the phenomena as exhibited in these different races. I have been told that in northern Michigan these Jumpers are to be found, but have obtained no evidence on that point that is entirely satisfactory. It would not be improbable that this assertion should be proved to be true, since the class among whom Jumpers are found is somewhat migratory, although not so much so as the English and Americans.
Origin and Philosophy of the Disease.—Jumping is probably an evolution of tickling. Some, if not all, of the Jumpers, are ticklish—exceedingly so—and are easily irritated by touching them in sensitive parts of the body. It would appear that in the evenings, in the woods, after the day's toil, in lieu of most other sources of amusement, the lumbermen have teased each other, by tickling, and playing, and startling timid ones, until there has developed this jumping, which, by mental contagion, and by practice, and by inheritance, has ripened into the full stage of the malady as it appears at the present hour. This theory is in harmony with the general facts of physiology, and explains, better than any suggestion that has occurred to me, the history of what would otherwise appear to be without explanation, and almost outside of science. In a certain sense, we are all Jumpers; under sudden excitement, as of a blow, or a violent, unexpected sound, any person, even not very nervous, may jump and cry, somewhat as these Jumpers do, though not with all the manifestations of the Jumpers. Hysterical women, jumping and shrieking on slight excitement, we have all seen.
Everything about this subject is incredible. I do not expect that my readers will believe all, if they believe any, of what is here reported; rather they will find it easier to believe that I have been deceived; that the six sources of error that are involved in all experiments with human beings were not fully eliminated; that the Jumpers, in short, experimented with me, and not I with the Jumpers; and that, through all of this half century, the guides and physicians, the proprietors of hotels, and their neighbors, and relatives, and friends, have been the victims of intentional or unintentional fraud. But to
