INTERREACTIONS OF TOXIN AND ANTITOXIN 3 



which gives partial neutralization phenomena quite similar to 

 those we have described as occurring with diphtheria toxin, and 

 also declines in toxic strength, but not in combining capacity, 

 forming toxoids. It was, however, the researches of Arrhenius 

 and Madsen which led to the establishment of the theory on a 

 sound basis. Madsen had previously investigated the constitution 

 of the haemolysin of tetanus (tetanolysin), working on Ehrlich's 

 lines, and had found it to consist of proto-, deutero-, and trito- 

 toxin, and a large amount of toxone. The substance was much 

 more convenient to work with than diphtheria toxin, since a constant 

 emulsion of red blood-corpuscles could be used as test objects 

 instead of guinea-pigs, and thus the experiment could be multi- 

 plied at will ; and when Madsen added the antiserum in small 

 amounts he found that the apparent irregularities due to the 

 presence of these various forms of toxin disappeared, and the 

 curve of neutralization is represented by a curve similar to that 

 given above, as illustrating the reactions between boracic acid 

 and ammonia. Thus : 



2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 



FIG. 20. CURVE OF NEUTRALIZATION OF TETANOLYSIN (MADSEN) 



62 



