io8 Scientific Proceedings (91). 



a lower resistance than slowly growing tumors. Similar deter- 

 minations on plant galls (supplied by Dr. Irvin F. Smith) indicate 

 that plant tumor tissues are uniformly more permeable than 

 normal plant tissues, the tumor tissues frequently exhibiting, 

 under reasonably comparable conditions, a conductivity more 

 than twice that of normal tissues. The observations of McClen- 

 don, Gray, etc., that sea urchins' eggs exhibit an increased con- 

 ductivity during the first stages of development harmonize with 

 the above observations on cancer tissue and lend support to the 

 conclusion previously reached by the writer, as a result of chemical 

 analysis of mouse tumors and blood reactions exhibited in cancer 

 and pregnancy, that both normal and pathological proliferative 

 processes depend upon an increased permeability of the protoplas- 

 mic film to water and water-borne food stuffs. 



An attempt will be made in the next paper to indicate briefly 

 by means of a physical model, the mechanism whereby changes 

 in protoplasmic permeability may be induced by changes in chem- 

 ical and physical environment and in a subsequent paper to apply 

 the principles involved to cancer. 



175 (1353) 



On the action exerted by antagonistic electrolytes on the elec- 

 trical resistance and permeability of emulsion membranes. 



(Preliminary note.) 



By G. H. A. Clowes. 



[From the Gratwick Laboratory, Buffalo, N. Y.] 



Artificial emulsion membranes suitable for electrical conduc- 

 tivity and permeability experiments may be prepared by inter- 

 posing layers of filter paper saturated with an emulsion of oil in 

 soap between supporting sections of rubber tubing in a glass U-tube 

 of the type commonly employed for electrical conductivity deter- 

 minations. A thicker layer or film of emulsion is generally pref- 

 erable and may be prepared by introducing into the U-tube a 

 section of rubber tubing of any desired length which is then filled 

 with emulsion. Retaining layers of filter paper above and below 



