148 E. E. FREE 



might be to produce phase inversion or, conversely, the initial 

 effect of an inverting agent might be to make the globules swell. 

 Although change in water distribution appears to be a simpler 

 and more effective mechanism for the ordinary regulation of per- 

 meability, it does not follow that phase inversion is impossible 

 as an extreme case of the same process. Both effects might re- 

 sult in turn from, for instance, a progressive change of the sur- 

 face tension at the interface between the phases. The behavior 

 of cells to ether, chloroform and other anesthetics is of interest. 

 Small concentrations of these substances decrease permeability; 

 large concentrations increase it.^^ The decrease is reversible; 

 the increase is not. May not water interchange and phase 

 inversion be in turn involved in these effects? 



It must be borne in mind also that the result of long continued 

 transfer of water between the phases is finally the same as though 

 the phases had been inverted. A system consisting of a dilute 

 external phase and a concentrated internal phase may become a 

 system having a concentrated external phase and a dilute internal 

 phase, not because of phase inversion by which the external 

 phase has become the internal, but because of interchange of 

 water by which the concentrated phase has become the dilute. 

 The end result is the same; the path by which it was reached is 

 different. 



As to the chemical nature of the two phases which might exist 

 in protoplasm and function in the way assumed, it is possible to 

 say little. It is interesting, however, that the work of Loewe 

 already mentioned indicates that some lipoid substances can 

 form colloids of this type. The assumption of a lipoid-water 

 colloid would explain the remarkable series of facts adduced by 

 Overton in support of his lipoid theory as well as the facts which 

 have been urged as inconsistent with this theory. In a sense 

 this would be a revival of the "mosaic" theory of Nathansohn 

 but on a different physical basis. In this connection it is of 

 interest that Calugareanu^* has observed a swelling of the glob- 



" Lillie, Amer. Jour. Physiol. 29: 372-397 (1912); 30: 1-17 (1912); Osterhout, 

 Sciences?: 111-112 (1913). 



18 Biochem. Zeits. 29: 96-101 (1910). 



