27 1 STUDIES IN IMMUNITY 



antitoxin unresistingly. The difficulty in such a reaction naturally 

 depends on the toxins and antitoxins under consideration,* and it 

 is probable thai the stability of the complex will vary in different 

 instances. It the complex is very stable, an additional T will remain 

 intact; on the other hand, it is readily attenuated when the complex 

 is unstable. 



It would seem quite evident from a recent experiment of Mor- 

 genroth'sf that these various possibilities may well exist. 



This investigator sensitized well-washed red blood cells with 

 their specific serum (55 degrees), centrifugalized, removed the 

 supernatant fluid and washed the corpuscles several times in salt 

 solution. The resulting sensitized corpuscles were suspended in 

 a medium that contained no free sensitizer. To such a suspension 

 he then added normal unsensitized corpuscles of the same sort. 

 If alexin in moderate amount is immediately added to such a mix- 

 ture, only part of the corpuscles are destroyed, namely, only those 

 that were sensitized. But if some time elapses before the alexin 

 is added, all the corpuscles are hemolyzed indiscriminately. Mor- 

 genroth very properly draws the conclusion that the normal cor- 

 puscles are able after a certain interval to remove a certain amount 

 of sensitizer from the sensitized corpuscles.^: In other words, a 

 change in distribution of the sensitizer analogous to the change in 

 distribution of the anti-alexin in the preceding experiment has 

 taken place. 



It is evident that the complex formed by the union of the sen- 

 sitizer with the fixing substance of the cell (which may be designated 

 CS 2 ) gives up a part of its sensitizer to other cells rather easily and 

 becomes, say, CS. In this instance the complex is rather unstable. 

 We may compare this result with the one noted at the beginning 

 of this article, which dealt with the effect of adding alexin in a single 

 or in divided doses to sensitized cells, in which instance the com- 

 plex " cell-sensitizer-alexin " (or, better, stroma-alexin) is remark- 

 ably stable. Destroyed blood cells laden with alexin do not yield 



* And even with a given toxin and antitoxin the more or less complete satura- 

 tion of the complex must be considered. A complex TA* would probably give 

 up its antitoxin more readily than does TA 2 . 



t Munch, med. Wochenschnft, 1903, No. 2. 



t It is also quite probable, as Morgenroth states, that the fluid serves as a 

 medium of passage for the sensitizer from one cell to the other. 



