LONG-RANGE FORCES 



43 



It is plain that the phenomenon of micelle formation 

 enables us to furnish a plausible explanation of some of 

 the peculiar properties of certain drugs. It is necessary 



Micelle formation 



Surface tension 



Permeability to 

 hexyl resorcinol 



»- Concentration of soap 



Fig. lo. The prevention of permeation of hexyl resorcinol into Ascaris 

 by micelle formation in a soap solution (After Trim and Alexander) 



to remark here that the complete establishment of these 

 theories requires more than the demonstration of a coin- 

 cidence between micelle formation and the onset of a 

 change in the action of a drug. 



Long-Range Forces 



Recently the biologist has become interested in rel- 

 atively long-range forces, i.e. forces operating over dis- 

 tances of the order of 25 A.U. up to several ^. Bernal 

 and Fankuchen have shown that in some types of col- 



