CONVERSION OF CHEMICAL ENERGY 85 



The conditions of membrane equilibrium described on 

 p. 56 can all occur in a system of two immiscible fluids, as 

 can also the high resistance to the electrical current. 



Whether cells are surrounded by semi-permeable membranes 

 or not, the following conclusions are warranted in regard to 

 the subject : 



1 . The unequal distribution of substances between cells and 

 their surroundings is explicable on either assumption, but the 

 production of the unequal distribution is not possible if the 

 membrane is impermeable to the substance that accumulates 

 inside. 



2. Plasmolysis and Turgor may be produced by osmotic 

 pressure acting on a semi-permeable membrane or by an effect 

 on the vapour pressure of an immiscible liquid. 



3. Haemolysis or Cytolysis will occur by rupture of a semi- 

 permeable membrane or by decrease of surface tension allowing 

 two immiscible fluids to mix. 



4. The high electrical resistance of cells may be due to a 

 membrane impermeable to ions or to two liquids that do not 

 exchange ions with each other. 



5. Amceboid movement and cell division can be explained 

 by surface tension changes at the junction of two immiscible 

 liquids but amoeboid movement cannot occur if a membrane 

 is covering the cells. 



Different conditions may hold in different cells. An 

 amoeba has no surface membrane, but red blood corpuscles 

 must have some structure because their shape is impossible 

 if surface tension is allowed to act on a free surface, and there 

 are ghosts left when the contents of the corpuscles have 

 escaped. 



The surface membrane of the red blood corpuscle may be 

 merely a permanent modification of the temporary gelation 

 produced on the surface of free cells. 



The presence of a membrane does not necessarily mean that 

 the membrane is impermeable to inorganic ions because it 

 may act merely by retaining cell colloids and the inorganic 

 constituents may be unequally distributed according to some 

 process associated with the application of the phase law to the 

 system of colloid cell contents and inorganic solution outside 

 the cell. 



It must not be forgotten that cells are living structures and 

 capable of acting as energy transformers. The characteristic 

 property of living organisms is their regulative action on 

 chemical processes. 



