THE EQUILIBRIUM BETWEEN HEMOLYTIC SENSITIZER 



AND RED BLOOD CELLS IN RELATION TO 



THE HYDROGEN ION CONCENTRATION. 



By CALVIN B. COULTER.* 

 {From the Hoagland Laboratory, Brooklyn.) 



(Received for pubKcation, December 22, 1920.) 

 INTRODUCTION. 



The reversible nature of the union between various kinds of antigen 

 and antibody in the usual physiological saline solution has been 

 demonstrated many times. ^^^^ Landsteiner and Jagic^ have inter- 

 preted the reaction between antigen and antibody as a reversible 

 reaction which is essentially similar to that taking place between 

 simpler and definitely known chemical substances and in which an 

 equilibrium is reached depending upon the concentration of the 

 reacting substances and the temperature. Further evidence that 

 suggests such an equilibrium state is given by BaiP and Matsui^'^ 

 in experiments on the splitting off of anticholera sensitizer. How- 

 ever, this point cannot be regarded as definitely proved by experiment. 



That the chemical reaction, or the acidity or alkalinity, is a factor 

 in the combination of antibody and antigen appears in any event 



* Van Cott Fellow in Pathology. 

 ^ Landsteiner, K., Milnch. med. Woch., 1902, xlix, 1905. 

 ^Morgenroth, J., Munch, med. Woch., 1903, 1, 61. 

 ^ Landsteiner, K., and Jagic, N., Milnch. med. Woch., 1903, 1, 764, 

 ^Landsteiner, K., and Jagic, N., Miinch. med. Woch., 1904, li, 1185. 

 ^Landsteiner, K., and Reich, M., Centr. Bakt., Ite Abt., Orig., 1905, xxxix, 83, 

 712. 



^ Bail, O., and Tsuda, K., Z. Immunitatsforsch., Orig., 1908-09, i, 546. 

 ''Tsuda, K., Z. Immunitatsforsch., Orig., 1909, ii, 225. 

 ^ Spat, W,, Z. Immunitatsforsch., Orig., 1910, vii, 712. 

 ^ Bail, 0., Z. Immunitatsforsch., Orig., 1914, xxi, 202. 

 ^"Bail, O., and Rotky, K., Z. Immunitatsforsch., Orig., 1913, xvii, 566. 

 ^^ Matsui, I., Z. Immunitatsforsch., Orig., 1915, xxiii, 233. 

 ^2 von Liebermann, L., Biochem Z., 1907, iv, 25; Arch. Hyg., 1907, Ixii, 277. 



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