Factor Controlling Cell Metabolism. 



589 



We arrive at a similar confirmation of the relation of surface-active substances 

 to cell metabolism, when we examine the substances which, as Loeb has shown, 

 affect the metabolism of unfertilised eggs in such a way that they either 

 produce cytolysis or, under certain conditions, incite artificial partheno- 

 genesis. The substances which belong to this group — narcotics, saponin, 

 soap, bile salts — are all substances which are strongly surface active. 



