pO TOXIN AND ANTITOXIN 



Dysentery toxin was first demonstrated by Conradi. Subse- 



Dysentery quently from experiments by Rosenthal, Todd, Kraus and 



Toxin. Doerr, etc., it became evident that this was a true toxin and not 



an endo toxin as was originally considered. Only the Kruse- 

 Shiga type of bacillus forms a toxin; for the Flexner type, no definite toxin 

 has as yet been isolated. Recent investigators, however, especially Kraus 

 and Doerr, are inclined to consider the human dysentery of the Kruse- 

 Shiga origin in the light of an intoxication or toxemia similar to diphtheria. 

 The lesions in the large intestine where the bacteria accumulate can be 

 compared to the diseased diphtheria tonsils, while the other manifestations, 

 as the cerebral symptoms, cardiac disturbances, nervous sequelae, eye 

 affections, etc., can be taken as expressions of the toxemia. 



Like the other described toxins, the dysentery toxin can be obtained by nitration of 

 bouillon cultures. The meat infusion must be quite alkaline. The optimum alkalin- 

 ity, according to Doerr, is obtained by adding 0.3 per cent, soda to litmus neutral 

 bouillon. The precipitate thus formed which increases on sterilization should not be 

 removed by nitration. Doerr also advises finely powdered chalk (20 gms. pro liter) to 

 be added to the weakly alkaline bouillon before the last sterilization. The toxin is 

 formed very gradually; the maximum is derived after two to three weeks. The gray 

 white pellicle upon the surface of the culture can be taken as an indicator for the amount 

 of toxin present. 



According to Kraus a good dysentery toxin can also be made by emulsifying the 

 bacteria (grown upon agar) in physiological salt solution and filtering through 

 Reichel niters. 



The toxicity of individual strains of dysentery bacilli varies greatly. 



The strength of the toxin is diminished by heating for one to two hours at 60 C. 

 Higher temperatures destroy it: 80 C., in three minutes and 90 to 100 C. in one 

 minute. 



Acids destroy the toxin probably by the formation of a non-poisonous compound. 

 The addition of a strong alkali restores the toxicity. 



Its preservation can be accomplished in a fluid state under the cover of toluol. 



The action of dysentery toxin can best be studied by its effect upon 

 rabbits after intravenous inoculation. Large doses kill the animals in 

 very short time, six to seven hours. The ordinary lethal dose produces 

 characteristic symptoms consisting of paresis, diarrhea, which may be 

 bloody, paralysis of the bladder, hypothermia, etc. Death takes place in 

 three to four weeks. 



Given subcutaneously, or intraperitoneally, the toxin has only a very 

 mild action. The incubation period is especially prolonged. Given per 

 os, no effect is in evidence. 



Besides rabbits the other susceptible animals (to large doses) are monkeys, cats 

 and dogs; chickens, pigeons and guinea-pigs are, in the opinion of Kraus and Doerr, 

 not at all affected by the toxin. 



