376 THE POPULAR SCIENCE MONTHLY. 



vests of introduced plants. To show their number, witness the long 

 lists given by Mr. Isaac Martindale of those found near Philadelphia, 

 and of Mr. Charles Mohr, of Alabama, of those found at Pensacola, 

 New Orleans, and other places. Wars, too, are the means of spreading 

 plants. It is said that great numbers of new plants have been found 

 in France, in the vicinity of places where the Germans had brought 

 forage for their horses and stacked it. Of course, many plants intro- 

 duced in this way do not thrive longer than a year or two, but some 

 of them no doubt take up their residence permanently. Man's pro- 

 pensity to seek out attractive plants in far-off countries, and to trans- 

 plant them to his home to make his garden attractive, has been the 

 means of the naturalization of many species. These have ample op- 

 portunity to escape into the surrounding country, and with favorable 

 conditions to spread extensively in all directions. Seeds of many 

 weeds are mixed with the wheat and other grains which man carries 

 with him wherever he goes, and plants wherever he may happen to 

 settle. Railroads are efficient agents in the work. Seeds are lodged 

 on the platforms of the cars, are carried along by the wind created 

 by the passing trains, and in many other ways are distributed along 

 the track. There is an instance of the work of the railroad in the east end 

 of Cincinnati, near Fulton, on the Little Miami Railroad. For the last 

 two or three years there have been growing great numbers of Euphorbia 

 marginata, a plant which is a native of the plains of Kansas, and which 

 is slowly but surely working its way toward the East by means of the 

 railroads. Eastern plants, which a number of years ago were wanted 

 in exchange with the West, are now naturalized in the West, and vice 

 versa. 



-o-**- 



HYSTERIA AND DEMONISM * 



A STUDY IN MORBID PSYCHOLOGY. 

 By CHARLES RICHET. 



III. 



THE mysterious problem of somnambulism is closely connected 

 with the study of the demoniac affection. It is necessary to 

 enter into some details on this subject, for we should not be able 

 to comprehend the nature of certain epidemics of the middle ages 

 if we were not acquainted with the different symptoms of the sleep 

 called magnetic. Moreover, the effrontery of charlatans has mixed 

 up so many absurdities with the real facts appertaining to this mal- 

 ady that it is hard for persons who have not made a special study 

 of it to preserve a just mean between the credulity that admits 



* Translated from the " Revue dcs Deux Mondes " by W. H. Larrabee. 



