538 
PHYSIOLOGY: W. O. FENN 
In pure NaCl there was no precipitation and the corpuscles wandered 
to the anode. In excess of cerium there was no precipitation and the 
corpuscles wandered to the cathode. These results become intelligible 
if the point of maximum precipitation is an isoelectric point due to the 
predominating effect of the CI ion (of NaCl) in the presence of the 
trivalent cerium cation. 
From these experiments it may be reasoned that antagonistic salt 
solutions produce a precipitate or a state of aggregation of an iso- 
electric nature in protoplasm. Physicochemically, therefore, a physio- 
logically balanced solution would be merely a mixture producing high 
precipitability. By varying the amount of the precipitate changes in 
the permeabiUty of the protoplasm might be brought about. 
In connection with the hypothesis developed here attention may be 
called to the suggestion of Loeb^^ that antagonism between salts and acids 
furnishes an excellent parallel to the results of Procter on gelatin and 
indicates that the protoplasmic substances which are responsible for 
antagonism are protein in nature. 
Summary. — 1. The experiments on gelatine support the hypothesis 
that anions antagonize cations in their effects upon organisms. 
2. The hypothesis here developed resembles that of Clowes except 
that it requires that NaCl should antagonize any electrolyte which has 
either a strong anion or a strong cation. 
3. The point of maximum antagonism is an isoelectric point at which 
the amount of alcohol needed for precipitation is at a minimum, and the 
aggregation or amount of precipitation is at a maximum. 
1 Loeb, These Proceedings, 1, 473 (1915). 
Clowes, /. Phys. Chem., 20, 407 (1916) and Science, 43, 750. 
3 Chick and Martin, Koll.-Chem. Beihefte, 5, 49 (1915). 
^ PauH, Biochem. Zs., 24, 239 (1910). 
^Pauli, KoUoid Zs., 12, 222 (1913); 7, 241 (1910). 
* Paub' u. Wagner, Biochem. Zs., 27, 296 (1910). 
« For "additive effect" see Osterhout, BoL Gaz., 58, 178 (1914). 
' This is true at least in low concentrations. In higher concentrations, the results are 
compHcated by other factors and have not been fully determined. 
* These proportions would be expected to vary with the medium used and the conditions 
of the experiment. Clowes (I.e.) finds that the critical point for NaCI and CaCl2 in oil- 
water emulsions varies between 500 to 1 and 10 to 1. 
^ Clowes has shown that in critical mixtures of NaCl and CaCl2, the phases of a water- 
oil emulsion separate out. 
i« Mines, G. R., Koll.-Chem. Beihefte 3, 191 (1912). 
''Science, 34, 653 (1911) ; Biochem. Zs. 33, 489 (1911) and 47, 127 (1912). 
