SCIENTIFIC PROCEEDINGS. 



Abstracts of Communications. 

 Fifty-fifth meeting. 



Cornell University Medical College, October 15, 1913. 

 President Ewing in the chair. 

 1 (818) 



On reversible emulsions and the role played by electrolytes in 

 determining the equilibrium of aqueous oil systems. 



By G. H. A. Clowes. 



[From the Biological Chemical Department of the State Institute for 

 the Study of Malignant Disease, Buffalo, N. Y.] 



The "oil-water" emulsion obtained by shaking equal volumes 

 of olive oil and water with a sufficient amount of n/10 NaOH to 

 render the external aqueous phase alkaline to phenol phthalein, 

 may be readily converted into a "water-oil" emulsion by shaking 

 with a solution containing an amount of CaCl2 slightly in excess 

 of the chemical equivalent of the NaOH employed in the prepara- 

 tion of the "oil-water" emulsion. The resulting "water-oil" 

 emulsion may be re-converted into an "oil-water" emulsion by 

 shaking with further additions of NaOH until the total amount of 

 that substance in the system slightly exceeds the chemical equiva- 

 lent of the CaCl2 previously employed. 



When chemically equivalent proportions of Ca and OH are 

 employed in a system containing equal volumes of oil and the 

 aqueous phase, neither type of emulsion appears to predominate. 

 At this critical point the system is in a state of extremely unstable 

 equilibrium. Shaking with a trace of NaOH solution converts 

 it almost instantaneously into an "oil-water" emulsion, while a 

 trace of CaCl 2 exerts the reverse effect, a "water-oil" emulsion 

 being formed. 



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