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 striking 

 differences. Although both are wound infections caused by characteristic 

 bacteria, smears of the pus from wounds, in the case of anthrax, dis- 

 play on examination numerous bacilli, while in the case of tetanus, the 

 bacillus is very sparsely found. Even carefully prepared anerobic cultures, 

 or inoculations in mice of the pus itself, do not always demonstrate the 

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

 cases, excessively large numbers of microbes can be found, 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 in- 

 vading 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 role, the entire symptom-com- 

 plex being produced by a poison extruded from the bacteria. In diphthe- 

 ria, 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 the bacteria in diphtheria is con- 

 fined to organs not absolutely essential for life diseased tonsils these 

 themselves do not explain the alarming situation observed in this disease; 

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

 by the bacteria, 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 

 the bouillon cultures of both diphtheria and tetanus. As most cultures 



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