498 THE POPULAR SCIENCE MONTHLY. 



solar system has been evolved ? Even the solar system is but one out 

 of one hundred million such systems, each of which has its own life- 

 history. Viewed in their true proportions, the phenomena I have de- 

 scribed are but of infinitesimal importance, and the time they have 

 occupied is merely ephemeral. 



No doubt we have only dwelt upon the tides on the earth and the 

 tides in the moon, which have been of such infinite importance. But 

 do not suppose that tides are confined to the earth and to the moon. 

 So far as we know, every body in the universe is capable of producing, 

 and actually does produce, tides in every other body. Every planet 

 throbs in response to the tides produced in it by every other planet. 

 Every star has a distinct tidal wave produced in it by every other star. 

 You may say that such tides are infinitesimal, but you must remember 

 that infinitesimal causes, sufficiently often repeated, can achieve the 

 mightiest effects. 



We know that tides have wrought our solar system into its present 

 form ; and are we to say that the wondrous powers of the tides have 

 no grander scope for their exercise ? I prefer to believe that tides 

 operate far and wide through the universe, and that in the recognition 

 of the supreme importance of tidal evolution we mark a great epoch 

 in the history of physical astronomy. Nature. 



EPIDEMIC CONVULSIONS.* 



By DAVID W. YANDELL, 



PEOFESSOB OF SUBGERY, UNIVERSITY OF LOUISVILLE, KENTUCKY. 



EXTRAORDINARY interest was excited in the popular mind of 

 Kentucky, at an early day, by a form of convulsive disease, 

 which, though it had been witnessed elsewhere in the world, had never 

 before assumed a shape so decidedly epidemic. Among the Camisards, 

 or French prophets, who appeared in the mountains of the Cevennes 

 toward the close of the seventeenth century, the subjects, when about 

 to receive the gift of prophecy, were often affected with trembling and 

 fell down in swoons. When the fit came, no matter where they were, 

 they fell, smiting their breasts with their hands, crying for mercy, 

 and imprecating curses on the Pope. They were finally, after an ob- 

 stinate struggle, put down by their insane persecutor, Louis XIY.f 

 Epidemic convulsions prevailed in Scotland, half a century later. 



* The larger part of the materials contained in this paper were collected by my father, 

 the late L. P. Yandcll, M. D., and were intended to be embraced in the "Medical History 

 of Kentucky," a work on which he was engaged at the time of his death. I have done 

 little more than arrange and place them in their proper chronological order. D. W. Y. 



f "Encyclopaedia Americana," article "Cevennes." 



