PROPERTIES OF ANTISENSITIZERS. 295 



property that blood cells have of extracting their specific sensitizer 

 from heated hemolytic serum, we are able to simplify the toxic solu- 

 tion, or, in other words, to isolate the toxin to be tested with the 

 antitoxin. And the fact that the normal sensitizers of normal 

 rabbit serum (which are not toxic for the ox corpuscles, but have 

 as great an affinity for the antitoxin as the specific sensitizer), when 

 added to neutralized toxin (i.e., sensitized corpuscles + antiserum), 

 liberate it by uniting with a certain amount of antitoxin, may allow 

 us to determine the law that governs the equilibrium between 

 antagonistic substances. But we shall not discuss in the present 

 article the theories of the interaction of toxins and antitoxins, as our 

 researches on this subject are not yet finished. We may simply 

 mention a fact that would seem to indicate that the destruction 

 of toxin by antitoxin is rarely absolute — whether because the re- 

 action is incomplete, so that the mixture always contains traces 

 of free toxin (Arrhenius and Madsen), or because, as we believe, the 

 neutralization of a toxin by an antitoxin is, in reality, simply a 

 greater or less attenuation depending on whether the toxin fixes 

 more or less antitoxin. According to our hypothesis the two 

 substances unite in variable properties and may therefore give 

 rise to a series of combinations ranging from free toxin to com- 

 pletely saturated toxin, being less and less toxic (without becoming, 

 of necessity, quite non-toxic) in proportion to the increase in anti- 

 toxin. As we know, Ehrlich's toxons, which occur in mixing a 

 toxin with an incompletely neutralizing dose of antitoxin, represent 

 in Arrhenius and Madsen 's conception small amounts of free toxin; 

 according to our conception they are toxic molecules insufficiently 

 saturated with antitoxin in which the toxicity is simply decreased 

 without being eliminated. It would seem to us, then, that in mix- 

 ing antiserum and sensitizer we form toxons from the toxin, in that 

 the sensitizer, when affected by antiserum, is simply weakened, but 

 not deprived of its original power. The sensitization is, as we know, 

 very slight, so that under the ordinary conditions of experimentation, 

 that is to say, in a mixture containing serum, the red blood cells 

 remain intact. The sensitizing power has not, however, been 

 entirely destroyed, for we find evidence of it if the corpuscles are 

 made less vulnerable by being placed in a less favorable medium 

 (salt solution) ; in other words, under conditions that facilitate sen- 



