ICp LECTURES ON IMMUNITY 



cording to Kyes and Sachs, staphylolysin is not acted 

 upon by cholesterin. 1 Madsen has even found that other 

 constituents, and not the cholesterin alone, protect erythro- 

 cytes against tetanolysin (still unpublished). 



The action of different anti-bodies on their correspond- 

 ing poisons is supposed to consist in a simple neutralisa- 

 tion, molecule for molecule. That the process is followed 

 by another phenomenon is indicated by the circumstance 

 that at high concentrations of antitoxin, where it is in 

 excess beyond the toxin present, the calculated values are 

 often found to exceed remarkably the observed ones. An- 

 other phenomenon also, discovered by Danysz, 2 indicates 

 that an excess of antitoxin exerts a perturbing influence. 

 Danysz investigated the toxicity of mixtures of ricin with 

 antiricin. He observed that a mixture of a parts of ricin 

 with b parts of antiricin is less toxic if the two constituents 

 are mixed at once, than if a fraction of a, say one-half, is 

 added to the b parts of antitoxin, and after a time the rest 

 of the toxin added to the mixture. The same phenomenon 

 was observed in diphtheria poison by von Dungern, and 3 

 with tetanolysin, staphylolysin, and rennet by Sachs. 4 

 On the other hand, the cobra poison does not display this 

 behaviour. 



To elucidate this remarkable phenomenon, which seems 

 to indicate that the same quantity of poison may bind dif- 

 ferent quantities of antibody, a large number of experi- 

 ments were carried out on tetanolysin by Madsen, and I 



1 Kyes and Sachs: Berl. klin. Wochcnschrift, Nos. 2-4 (1903). 



2 Danysz: Ann. de PlnsL Pasteur, 1902. 



8 V. Dungern: Deutsche med. Wochenschrift, Nos. 8 and 9 (1904). 

 * Sachs : Centrtlbl. /. Baktcriologic, 37. Part II, 251 (1904). 



