40 COLLOIDS IN BIOLOGY AND MEDICINE 



in biological systems exerting under varying conditions a protective 

 or destructive effect on the protoplasmic film exhibit similar abnor- 

 malities in emulsion and drop systems. Magnesium salts function 

 as protective agents like calcium salts when added to a soap solution 

 which is passed through oil; but as destructive agents like NaOH, 

 NaCl or KC1 when added to a dilute solution of NaOH which is 

 passed through an oil containing fatty acid. 



Closely parallel results were observed between the drop system de- 

 scribed above, the process of blood coagulation, the lethal dose of 

 given electrolytes in mice when injected intravenously, the hemolysis 

 of blood corpuscles by complement and amboceptor, etc., a common 

 critical point being observed in these widely diversified systems. 

 CLOWES considers that these experiments lend substantial support to 

 to the view that while protoplasm as a whole consists of a system 

 approximating more nearly to a dispersion of the non-aqueous phase 

 in the aqueous, the extreme marginal layer of protoplasm may be 

 looked upon as an emulsion or gel-like system consisting of two con- 

 tinuous phases in which fluctuations in permeability to water and 

 water-borne substances may be caused by variations in the propor- 

 tions of metabolic products, electrolytes, etc., a slight change in the 

 system in the direction of water surrounded by the non-aqueous phase 

 leading to a diminution in permeability, while a change in the reverse 

 direction, towards a system in which the non-aqueous phase is more 

 completely dispersed in the aqueous, would lead to an increased 

 permeability. 



Substantial support is lent to this point of view by OSTERHOUT'S 

 observations that the conductivity of Laminaria tissue is raised by 

 exposure to a solution of NaCl, lowered by CaCl 2 , but unchanged 

 when exposed to a mixture containing 100 molecules of NaCl and 

 one of CaCl 2 . Life can only be maintained within certain ranges of 

 electrical resistance or permeability and an increase or decrease 

 in permeability beyond given limiting points is no longer reversible 

 and invariably causes death. WILDER D. BANCROFT: Jour. Phys. 

 Chem., 17, 501 (1913). G. H. A. CLOWES: Proc. Physiological Sec- 

 tion, International Medical Congress, pp. 105-114, London, 1913. 

 Proc. Soc. Exp. Biology and Medicine, 11, pp. 1-3, 4-5, 6-8, 8-10 

 (1913). Jour. Physical Chemistry, 20, p. 407 (1916). Proc. Soc. 

 Exp. Biology and Medicine, 13, pp. 114-118 (1916). Science, 43, 

 pp. 750-757 (1916). Tr.] 



