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Mr. W. Cramer. Surface Tension as a 



or to variations in their concentrations. And it may be pointed out here that 

 surface tension is affected by very slight quantities or changes in concentra- 

 tion of surface-active substances, particularly when the initial concentration 

 is low. Or interfaces may be formed, or disappear, as the result of chemical 

 changes, or become extended or shortened, and thus affect again chemical 

 changes, just as in the experiments with invertase the reaction was influenced 

 by extending the surface " glass " through the watery solution. We thus get 

 a conception how the cell regulates and controls its metabolism, how a chemical 

 change may accelerate or retard other chemical processes which may have no 

 chemical relation to it and which in vitro would remain unaffected by 

 it. It is thus possible to explain the chemical organisation of the cell 

 without having to postulate, as has hitherto been done (Hofmeister, 

 Hans Meyer), the existence of hypothetical membranes in the cytoplasm 

 which are supposed to separate the different chemical systems. 



The validity of this conception of surface tension and surface energy as 

 factors controlling cell metabolism is capable of being tested experimentally. 

 For, according to this idea, substances which do not affect the protoplasm 

 chemically (that is to say are neither bases nor acids, neither reducing nor 

 oxidising agents, etc.), but which are strongly surface active, should markedly 

 affect the metabolism of the cell. That is actually the case. The condition 

 of narcosis in which the metabolism of the cell is profoundly affected is 

 brought about by substances which fulfil these postulates. They do not affect 

 the protoplasm chemically and they are all strongly surface-active ; there is 

 even direct evidence that these substances influence the action of cell ferments. 

 For Chiari has shown that in the excised liver of anaesthetised animals the 

 process of autolysis proceeds more rapidly than in the liver of normal animals. 

 And Guignard has demonstrated that the effect of anaesthetics on laurel leaves 

 is to release the action of ferments, as evidenced by the production of hydro- 

 cyanic acid.* 



* In order to avoid misunderstandings, it may be pointed out here that these substances, 

 in addition, must be capable of penetrating into the cell. They do so by virtue of their 

 solubility in lipoids, according to the Meyer-Overton theory, or by virtue of their 

 " Haftdruck," according to J. Traube. These theories of narcosis enable us to understand 

 quantitative differences in the strength of different narcotics or in their action on different 

 tissues. But they do not enable us to understand how they act upon cell metabolism in 

 such a way as to bring about the state of narcosis when they have penetrated into the 

 cell, and it is this question which is being considered in this paper. 



Hans Meyer himself recognised this, and put forward as a further explanation the 

 assumption that narcotics soften the hypothetical lipoid membranes which surround each 

 molecule of ferment and substrate and keep them apart under normal conditions. Others 

 (Hober, Mansfeld, Gurber) have put forward different hypotheses to explain the state of 

 narcosis. 



