A DYNAMICAL THEORY OF ANTAGONISM. 



By W. J. V. OSTERHOUT. 

 (Read April 14, igi6.) 



When toxic substances act as antidotes to each other we ck.1 this 

 action antagonism. The writer has found that an accurate measure 

 of antagonism is furnished by the electrical resistance of living 

 tissues. A toxic substance causes a fall of resistance : but if another 

 toxic substance be added and the fall of resistance be thereby in- 

 hibited it is evident that this result is due to antagonism. The 

 amount of antagonism may therefore be measured by the fall of 

 resistance. 



A series of such measurements is reported in the present paper. ^ 

 The method of making these measurements has been previously 

 described. - 



The experiments consisted in determining the electrical resistance 

 of Laminaria AgardJiir in NaCl .52 M, in CaCU .278 M and in 

 various mixtures of these. 



In order that each solution might contain as nearly as possible 

 the same kind of material the following method was employed. 

 Seven disks were cut (by means of a large cork borer) from the 

 same part of a frond : each disk was placed in a separate tumbler of 

 sea water. A second lot of seven disks were cut, as close to each 

 other as possible, and placed in the tumblers, so that each tumbler 

 contained two disks. This was continued until each tumbler con- 



1 In an earlier series (Pringsheim's Jahrh. filr wiss. Bot., 54: 645, 1914) 

 the maximum antagonism was found in mixtures containing less NaCl than 

 is here reported. The present series comprises six sets of experiments (in 

 the earlier there were only three), was made at more nearly constant tem- 

 perature and with an improved technique. The later results may therefore 

 be regarded as more reliable. 



^Science. N. S., 35: 112, 1912. 



' This is the most common species at Wood's Hole, Mass. ; it was for- 

 merly identified as L. saccharina and is so referred to in earlier papers by 

 the writer. 



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