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power is considerably. impaired already hy a slight increase, of osmotic 
pressure of the medium, and that the nature of the substance occa- 
sioning the increase of osmotic pressure is not without importance 
indeed, but plays a subordinate part. ') 
More explicit communications on the investigations discussed in 
this paper will appear elsewhere. 
Physiology. — ‘About Observations on the electro-inyogram and 
Jorm-myogram under the influence of fatigue.’ By Dr. A. K.M. 
Noyons, assistant in the Physiological Laboratory at Utrecht. 
(Communicated by Prof. H. ZWAARDEMAKER.) 
(Communicated in the meeting of December 24, 1908). 
As a consequence of my investigations in which the independence 
of the electro-cardiogram with regard to the form-cardiogram *) came 
to light, the question rose whether also for a skeleton-muscle a 
similar independence exists between electric changes and changes 
of form under certain definite circumstances. In order to get data 
with respect to this I started from the principie that in the course 
of a process of fatigue, arisen by regularly repeated stimulation, 
different forms of contraction with changes in erescente and different 
forms of contraction-state as tetanus and tonus can be revealed. 
It is the mutually deviating physiological conditions in the course 
of a process of fatigue which, as might be expected, with the 
existing independence of mechanical and electric reaction upon the 
same stimulus, would sooner or later break the congruence of these 
reactions prevailing at a given moment. Not long ago Bricker *), 
testing the data of Marrius,, WALLER, GARTEN and Duric pointed out 
cases of troubled parallelism. These investigators, in order to make 
the action-current visible, have made use of the capillar-electrometer, 
whereas I regularly availed myself in my investigations of the string- 
galvanometer of EINTHOVEN (EDELMANN’s small model). 
In order to cause contraction of the muscle both mechanical and 
1) Hampuraer en Hexma. These Proceedings June 1907, 
*) Noyons., A. K. M. About the Independence of the electro-cardiogram with 
regard to the form-cardiogram. These Proceedings October 31, 1908. 
5) Brücke, E. Th. v. Ueber die Beziehungen zwischen Aktionstrom und Zuckung 
des Muskels im Verlaufe der Ermiidung. Archiv f. d. ges. Physiologie Bd. 124, 1908. 
