ANTAGONISM 159 



were inhibited by a salt compound, formed by the union 

 of NaCl and CaCl 2 with some constituent of the proto- 

 plasm (certain of these reactions are accelerated 

 by CaCl 2 ). 



3. A quantitative theory is developed in order to 

 explain: (a) the toxicity of NaCl and CaCl 2 ; (b) the 

 antagonism between these two substances; (c) the fact 

 that the optimum proportions do not change with altera- 

 tions of concentration, and (d) the fact that recovery (in 

 sea water) may be partial or complete, depending on the 

 length of exposure to the toxic solution. 



It may be appropriate to call attention to some appli- 

 cations of this theory. Antagonism has been explained 

 by Loeb, and by the writer on the ground that antagon- 

 istic substances prevent each other from entering the 

 cell. As the writer has repeatedly pointed out 20 , this 

 explanation encounters a difficulty in the fact that 

 antagonistic substances penetrate the cell in a balanced 

 solution (although the penetration is much slower than 

 in unbalanced solutions). The proof of this has been 

 obtained by the writer by means of the method of plas- 

 molysis 21 as well as that of electrical resistance 22 ; it has 

 recently been confirmed by Brooks 23 by means of the 

 method of tissue tension as well as of diffusion through 

 a disk of living tissue and by direct determinations of the 

 penetrating substances made by the writer (see page 216). 



It is obvious that antagonistic substances must 

 penetrate from a balanced solution since otherwise the 

 cell could not obtain the salts necessary to its existence. 



20 Cf. Osterhout (1911, 1912, A, C, 1913, B). 



21 Of. Osterhout 1911. See page 214. 

 S2 G'/. Osterhout (1912. A. C; 1915, C). 



23 Cf. Brooks (1916, A. C.; 1917, B). See pages 206 to 209. 



