Ralph W. Webstek 



19 



TABLE XII 



interstitial spaces, fluid by capillary attraction, adsorption, and absorption. The recent 

 experiments of Greeley confirm this idea of change of structure under influence of 

 temperature and consequent change in absorptive power of muscle. 



VIII. THEORETICAL CONSIDERATIONS 



PERMEABILITY OF SARCOLEMMA 



In discussing the theoretical conclusions to be drawn from the experiments detailed 

 in this paper, the question to be first settled is whether the protoplasm of the muscle 

 is permeable and if so in which direction or directions and to what substances. 



It will be remembered that in former papers Lingle, Loeb, and Miss Moore called 

 attention to the fact that the rhythmical contractions of strips of turtle's ventricle, of 

 skeletal muscle, and of the lymph hearts of frogs, were under the influence of certain 

 ions. They further showed that electrolytes caused an effect while non-electrolytes 

 caused none. Loeb's explanation of the phenomenon noted in skeletal muscle was 

 that a certain physiological balance existed between the inorganic cations of the muscle 

 plasma. If this balance be disturbed certain phenomena, among them rhythmical con- 

 tractions of the muscle, are observed. He shows, as do also the other authors noted 

 above, that the contractions are due to the excess of Na ions beyond that physiologi- 

 cal relation existing between Na and Ca. If a muscle be immersed in a sodium 

 chloride solution Na ions, says Loeb, will penetrate the muscle and will gradually 

 replace the Ca, K, and other cations present. In about an hour rhythmical contractions 

 will begin and will last for some time. If, instead of an NaCl solution, a Na2S04 

 solution be used, these contractions appear at once, because, as he says, the physiologi- 

 cal relation has been disturbed both by entrance of Na ions and by the precipitation 

 of the Ca ions by SO4 radical. This latter result is more striking if an alkaline 

 oxalate or citrate solution be used instead of a sulphate solution. It was further 

 shown by these authors that Ca, K, Mg, Ba, etc., had exactly the opposite effect upon 

 rhythmical contractility, viz. , an inhibiting action. It seems quite evident, from these 



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