Proceedings, 181 



March 12, 1889. 



Seventeen persons present. 



A. D. Meeds was elected a member. 



Mr. C. G. MacMillan presented a paper on "Artificial Cells 

 and Osmotic Action." The paper consisted of a discussion of the 

 different varieties of artificial cells, particularly that of Pfeffer^ 

 and notes on some experiments made by the author at the Harvard 

 laboratories of Physiological Botany. 



Mr. Herbert G. Smith then read a paper on "The Jumpers," a 

 peculiar nervous disease occurring of late in northern Wisconsin. 



[abstract,] 



In northern Wisconsin, at Hayward and Mason, were observed several 

 acute cases of "Jumpers" analogous to those of Maine, described by Dr. 

 Beard* some time since. The subjects here are chiefly of French blood — 

 two Swedes being reported, although I cannot positively confirm this. 

 These cases are among working classes, chiefly lumbermen. The charac- 

 teristic nervous discharges are the occasion of the most extreme physical 

 and mental excitability, which, however, decreases with repetitions of the 

 same cause consecutively applied. In one case a trumpet, when sounded, 

 produced an acute excitation and explosive sounds. Imperative commands, 

 i. e., to strike, to jump, to clap the hands, to "let it drop," &c., &c., are in- 

 voluntarily obeyed. It is reported upon good authority that one case leaped 

 from a bridge upon which he was working a distance of twenty feet to water; 

 another threw a basket of crockery from his shoulder to the ground, both 

 from these causes. The effect decreases with successive excitations. Absence 

 , of excitability largely improves the condition of these cases, while aggra- 

 vation and frequent "shocks" intensify it, and in all cases produce great 

 bodily and mental distress. 



One family includes five cases of Jumpers, but I am uncertain whether 

 this and other similar indications point to a hereditary tendency in the com- 

 plaint, or more to a general disposition among close companions, especially 

 the young, to imitate a new peculiarity. 



April 2, 1889. 



Thirteen persons present. 



John B. Hawley was elected a member. 



Professor J. A. Dodge gave two ^'analyses of water used in a 

 , boiler employed for heating a public building in St. Peter, Minn. 

 (See paper DD.) 



Professor C. F. Sidener then discussed the reported decompo- 

 sition of cobalt and nickel, and, incidentally, the grouping of the 

 chemical elements on the basis of their physical relations. The 

 paper awakened some discussion, participated in by the reader of 

 the paper. Professor Dodge and Mr. Hawley. 



♦American Neurological Society, N. Y. 1880. 



