TOXINS AND ANTITOXINS 263 



Assuming, therefore, upon the foregoing considerations, that the 

 valency of antitoxin for toxin is 200, Ehrlich carries out his experi- 

 ments in the following way : 



Given a toxin, the unit (T) of which is 0.024 c.c., he first deter- 

 mines the L . dose which, tested against the standard antitoxin unit, 

 in this case Is 2.05 c.c. But 2.05 c.c. = 85 T. (or 2.05 -=- .024) units. 

 By mixing the L + dose of toxin and antitoxin in such a way that 

 the quantity of antitoxin is gradually increased, while the toxin 

 remains always L + , and determining upon animals the amount of 

 free toxin contained in each mixture, the following table may be 

 constructed : 20 



antitox. unit representing valencies + + = 85 free T units. 

 .1 " ll " 20 " -KL + = 85 " " li 



.25 " " " 50 " + + = 60 " ll " 



.8 " " " 160 " +L + =10 " tl " 



.9 " " li 180 " +L + = 3.5 " ll " 



It is plain that the substances with the strongest affinity for anti- 

 toxin must be bound first by the antitoxin. This does not diminish 

 the toxic value of the mixture ; and these are the protoxoids. Next 

 are bound syntoxoids and toxins, and, finally, the toxons. It is 

 plain that, by this method, the constitution of any given toxin may 

 be ascertained, and Ehrlich has constructed, on the basis of these 

 observations, what he terms his toxin spectrum. Minor differences 

 of toxicity and affinity for the antibody have caused him, by the 

 partial saturation method described, still further to divide toxin 

 into proto-, deutero-, and trito-toxin. 



His spectra graphically describe the constitution of any given 

 toxic bouillon and trace its deterioration as follows: 



Ehrlich 's opinions as to the constitution of toxin have borne 

 important practical fruit in allowing him to develop a system of 

 standardization of anti-toxin which will be considered in the next 

 chapter, but his theoretical conceptions as described above are not 

 accepted as truly representing the conditions at the present day. 

 His assumption of the complexity of toxic filtrates, that is, toxin, 

 the various toxoids, and toxons, results from strict adherence to the 

 belief that the reaction is analogous to that taking place between 

 strong acids and strong bases. The first to seriously throw doubt 

 upon his theoretical conceptions 011 the basis of experiment, were 

 Arrhenius and Madsen. 



Example taken from Ehrlich, Deut. med. Woch., 1898. 



