ACTION OF ANTITOXINS ON TOXINS. 271 



hemolysis in tube " d," it is due to an almost negligible trace 

 of free alexin; the next mixture, "e," which contains two addi- 

 tional minimal doses of alexin, should show complete hemolysis but 

 actually does show only partial hemolysis. Ehrlich's phenomenon, 

 then, is present, but is not well marked. It is also to be noted that 

 a volume of anti-alexin equal to that of the alexin must be used in 

 order to protect corpuscles effectively. 



The most interesting results are evident soon after the mixtures 

 are made, and, if the moment when hemolysis is complete 

 is noted, Ehrlich's phenomenon is then very striking. The mix- 

 ture of 1.2 c.c. of alexin and 0.3 of a cubic centimeter of anti- 

 alexin should, according to the hypothesis of neutralization in 

 fixed proportions, contain 0.3 of a cubic centimeter of neutralized 

 alexin and 0.9 of a cubic centimeter of intact alexin. In such a 

 mixture hemolysis is complete only after 70 minutes, which is at 

 least twice as long as is required in a mixture containing a single 

 fatal dose of alexin without antitoxin. Hemolysis is complete in 

 this latter mixture before it begins in the former. 



In mixtures of anti-alexin with doses of alexin from 0.4 to 0.9 

 of a cubic centimeter, corpuscles are eventually hemolyzed, the 

 rapidity in beginning and completion of the process varying directly 

 with the amount employed. For example, although hemolysis is 

 complete in 70 minutes in a tube with 1.2 c.c. of alexin, there is 

 none at this time with a dose of 0.9 of a cubic centimeter 

 ("/,"), 2| hours being necessary for complete hemolysis, and at 

 2^ hours hemolysis is only partial in tube "i," has barely begun in 

 tube "h," and so on. In short, the time necessary for the liberation 

 of hemoglobin varies indirectly with the amount of alexin employed. 



The experiment shows that a dose of anti-alexin that can com- 

 pletely neutralize 6 fatal doses of alexin (one-half hour) will check 

 24 fatal doses to such an extent that they produce less rapid hemoly- 

 sis than a single unaffected fatal dose. It is impossible, therefore, 

 to imagine that anti-alexin added to a large dose of alexin completely 

 neutralizes part of it, leaving the excess free: such mixtures do not 

 act at all as do simple dilutions of alexin. 



Anti-alexin affects all the alexin present equally, in accordance with 

 a law of varying proportions, as has just been fully explained. 

 Ehrlich's explanation for diphtheria toxin, presupposing the exist- 



