Physiology. — "Are contractility and conductivity two separate 

 propei'ties of the sheleton-musclea and the heart?'' ]^y Dr. S. 

 DE Boer. (Corainunicated by Prof. G. van Runberk). 



(Communicated in the meeting of September 29. 1917). 



In 1888 BiEDERMANN made experiments on skeleton-muscles, from 

 wliicli he concluded that under special circumstances these muscles 

 aie still irritable and have still retained their conductivit}', whilst 

 the contraclilit>- has ceased to exist. He placed the sartorius of frogs 

 over a certain length in water. When it had lain in it for some time 

 he stimulated the end of the sartorius that had been in contact with 

 the water. The result was, that the stimulated part of the muscle 

 that had been in the water, did not contract, but the other part did. 

 Engelmann repeated tiie experiment, and obtained the same result. 

 Engelmann applied this experiment likewise to the heart. He plunged 

 the auricles of frogs' hearts for some time into water, thereupon he 

 stimulated the auricles, and saw after doing so that the ventricle 

 contracted, whilst the auricles did not show any contraction at all. 

 Engelmann communicates his results in the following phrases : "Von 

 der Richtigkeit der Thatsache hatte ich mich durch eigene Versuche 

 am Sartorius curarisirter Frösche überzeugt Die Bestatigung ist 

 so leicht, wie das Resultat iiberraschend. Der Muskel wird in der 

 ganzen Ausdehnung, in welcher das Wasser ilm seiner Contractilitat 

 beraubt, gleichsam zum Nerv. So nun auch die Muskelbiindel der 

 Vorkaujuiern: sie verlieren im Wasser ihren Charakter als Aluskeln, 

 und behalten ihre Function als motorische Nerven der Kammer". 

 Further : "dass die Muskelfasern der Vorkammer auch nach voll- 

 standiger Aufhebung ihrer Contractilitat doch den Béwegungsreiz für 

 den Ventrikel noch fortzupflanzen im Stande sind, und zwar mit 

 einer Geschwindigkeit durchaus derselben Ordnung, wie wenn das 

 Verkürzungsvermögen erhalten ware". 



It has now appeared to me, that (he conclusions made from their 

 experiments by Biedermann and Engelmann, are entirely incorrect. 

 This may appear from the following experiments which I made with 

 regard to this problem. In the first place about the skeleton-muscles. 

 I attached a m. Gastrocnemius of a frog to a lever and plunged 

 the muscle into a solution of Ringer. Then I induced the muscle 



