CHAPTER VII. 

 TOXIN AND ANTITOXIN. 



So far, the preceding chapters have dealt with immunization by the 

 bacterial bodies and substances extracted from them. Further attention 

 must, however, be paid to the products of secretion of bacteria, namely the 

 toxins. Only few classes of bacteria have true soluble toxins such as are 

 possessed by tetanus and diphtheria bacilli. The symptom-complex incited 

 by the toxin producing bacteria differs decidedly from that of the sepsis 

 class. 



A comparison between anthrax and tetanus certainly exhibits a striking 

 difference. Although both are wound infections incited by characteristic 

 bacteria, smears of the pus from wounds, in the case of anthrax, display on 

 examination numerous bacilli, while in the case of tetanus, the bacillus is 

 very sparsely found. Even carefully prepared anerobic cultures, or inocu- 

 lations in mice of the pus itself, do not always successfully demonstrate the 

 presence of the tetanus bacillus. In the blood, lymph glands and viscera 

 of anthrax cases, excessively large numbers of microbes can be exposed, 

 while even in the most fatal cases of tetanus, there is nowhere any evidence 

 of bacteria or their spores. Where so many living foreign organisms are 

 found invading the individual, no hypotheses are necessary for explanation 

 of the associated marked disturbances as in anthrax; it is, however, more 

 complex to understand the severity of the symptoms in conditions like 

 tetanus, where such exceedingly scant bacteriological findings exist. Here 

 the micro-organisms play only a secondary r61e, the entire symptom-com- 

 plex being produced by a poison extruded from the bacteria. In diphtheria, 

 conditions are similar to those in tetanus, although in the former the bacilli 

 can be readily demonstrated both microscopically and by culture. Even 

 though, however, the localization of bacteria in diphtheria is confined to 

 organs not absolutely essential for life diseased tonsils these themselves 

 do not explain the alarming situation observed in this disease; for the real 

 cause of the illness is to be found in the toxin which is secreted by the 

 bacteria localized in them, and distributed by the blood stream throughout 

 the entire system. 



That a toxin really exists, and is not hypothetical, Roux and Yersin, as 

 well as Kitasato have proven by demonstration of the poisonous agents in 



68 



