PROTOPLASMIC PERMEABILITY 147 



in the other phase. Such sudden changes of permeabihty do not 

 appear to have been observed, nor has it been shown that in- 

 crease of permeabihty to one set of substances is accompanied 

 by decreased permeabiht}^ to another set. These objections 

 mip;ht be avoided in part by assuming a membrane in a state of 

 mobile equihbrium so that parts of it are always in one phase 

 relation and parts always in the invert-ed relation, or by assuming 

 a state of frequent alternation of the membrane from one phase 

 relation to the other. Such conditions are probably possible 

 of occurrence theoreticall}'" as dynamic equilibria, but the balance 

 would be extremely delicate and any slight disturbance would 

 destroy it completely, creating the condition of entire and sudden 

 reversal of permeability relations which does not appear to be the 

 rule. 



In his second paper^^ Clowes presents experimental evidence for 

 a parallelism between the effects of sodium hydroxide and 

 calcium chloride in producing phase inversion in emulsions of 

 olive oil and water and the effects of these same reagents on the 

 permeability of protoplasm. But this parallelism does not es- 

 tablish that the two mechanisms are the same. Olive oil and 

 water do not mix. Their emulsions do not have the property 

 of ready exchange of water between the phases, which property 

 characterizes the emulsoids of the gelatine type and probably 

 the colloids of protoplasm. Nothing similar to olive oil occurs 

 in the normal cytoplasm. The lipoid constituents of the cell 

 are not oils and have been shown by Loewe^'' to be capable of 

 forming with water, emulsoid colloids which appear to have this 

 property of water interchange. But, even if these differences 

 between the two cases are ignored, Clowes' evidence is not in- 

 consistent with the hypothesis here suggested. It is quite pos- 

 sible that the swelling of the globules which is here postulated 

 and the phase inversion which Clowes postulates could be pro- 

 duced by the same agent, for instance, calcium chloride, accord- 

 ing to the concentration in which it is used. Thus the ultimate 

 effect of adding an agent which caused swelling of the globules 



1* Jour. Phys. Chem., loc. cit. 



i« Biochem. Zeits. 42: 150-218 (1912). 



