EQUILIBRIA IN ABSORPTION PROCESSES 149 



typhoid bacilli and not by other bacteria, for instance not 

 by cholera vibrios, and vice versa. Probably the cell-- 

 membranes of typhoid bacilli are only permeable to typhoid 

 agglutinins, but not to other agglutinins. Normal sera con- 

 tain different agglutinins against bacteria and red blood- 

 corpuscles; by shaking them with the corresponding bacilli 

 or cells, it is possible to separate the different agglutinins. 

 Thus Malkoff mixed goat-serum, that agglutinates red 

 blood-corpuscles from man, rabbits, and pigeons, with red 

 blood-corpuscles from rabbits. The centrifugalised serum 

 had lost its agglutinating power for rabbit's erythrocytes, 

 but not for the two other varieties. 1 



The agglutinins lose their agglutinating power spon- 

 taneously, but much more rapidly at high than at low 

 temperatures (cf. pp. 87 and 91). Treatment with different 

 chemical agents, as hydrochloric and other acids, bases, 

 formol, and urea, weakens them. The details of these 

 circumstances have not been closely investigated. 



Just as agglutinins are absorbed by bacteria and red 

 blood-corpuscles, so in the same manner other different 

 substances are absorbed by these cells, and probably 

 analogous regularities are manifested in these cases. 

 Thus tetanolysin, ricin, and the different immune bodies 

 are absorbed by red blood-corpuscles ; and it seems to be 

 a general law that only such substances as are absorbed 

 by these cells exert an influence upon them. Whether the 

 cells are living or dead, seems, as we observed regarding 

 the absorption of agglutinins, to be quite immaterial if 

 the killing of the cells has been cautiously accomplished, 

 so that no notable chemical changes have occurred. 



1 Malkoff : Deutsche med. Wochenschrifi, 1900. 



