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INFECTION AND RESISTANCE 



toxin itself. Next are bound the toxins themselves together with 

 varying amounts of "syntoxoicls" which possess the same affinity as 

 toxin. Finally there are left the toxons which possess a lesser affin- 

 ity than toxins or toxoids, and therefore again have the discrepancy 

 between the L and L + dose. Ehrlich utilizes this method in order 

 to determine the composition of the constituents of any given toxic 

 filtrate and expresses the results in the so-called "toxin spectra." 



The construction of these spectra and the principles underlying 

 the measurements on which they are based are very clearly illus- 

 trated by Madsen, 17 from whose article the following type spectra 

 are taken : 18 



9 20 K> 40 M 60 TO 00 so too no 



TOXIN SPECTRUM AFTER MADSEN, Ann. de I'lnst. Past., Vol. 13, 1899, p. 57. 



This figure represents the diphtheria filtrate composed of 50 

 valencies of protoxoid, 100 toxin and 50 toxon equivalents. The 

 measurements in this case may be represented by the following tab- 

 ulation : 



LO -h 1 antitox. unit = 200 valencies = lethal dose 



Lo -j- .75 antitox. unit = 150 valencies = lethal dose 



L + .25 antitox. unit = 50 valencies = 100 lethal doses 



Lo -j- antitox. unit = valency = 100 lethal doses 



The following diagram, also from Madsen, represents the same 

 poison after it had deteriorated to ^ its toxic power. Lo, therefore, 

 would contain only 50 toxic doses. 



AFTER MADSEN, Ibid., p. 578. 



The measurements corresponding to this table are as follows: 



L + I . antitox. unit = 200 valencies = lethal dose 



Lo 4" .75 antitox. unit = 150 valencies = lethal dose 



Lo + .745 antitox. unit = 149 valencies = lethal dose 



Lo 4- -74 antitox. unit = 148 valencies = 1 lethal dose 

 etc. until 



17 Madsen. Ann Past., Vol. 13, 1899, p. 576. 



18 We have chosen to illustrate the principles of the toxin spectrum from 

 the article of Madsen rather than from Ehrlich's original work, because the 

 former presents this difficult phase of the subject in a hypothetical toxin of 

 extremely simple structure. Some of Ehrlich's spectra constructed from 

 actual measurements may be found in Deutsche med. Woch., No. 38, 1898. 



