SPECIAL PROPERTIES OF THE PRINCIPAL TOXINS 117 



lesions occurring in the intestinal canal are referable to the excretion of 

 dysentery toxin, rather than to the direct local action of the bacilli. 

 The action of the dysentery toxin upon animals is very characteristic, 

 and throws much light upon the disease in man. Intravenous injection 

 of the toxin in rabbits is followed by marked diarrhea, rapid fall in tem- 

 perature, respiratory embarrassment, and terminal paralysis. Upon 

 autopsy the intestinal mucosa, especially that of the cecum and colon, 

 shows marked inflammatory involvement, supporting Flexner's ob- 

 servation* of the necrotic action of excreted toxin. 



Dysentery bacilli also produce an endotoxin, and poisonous sub- 

 stances are easily obtained by extracting the bacilli themselves or by 

 filtration of properly prepared bouillon cultures. The toxin is fairly 

 stable, and well preserved under toluol in the refrigerator. 



5. Staphylolysin. Two definite toxins have been isolated from 

 cultures of Staphylococcus pyogenes aureus and albus, one of which 

 exerts a destructive action on erythrocytes (hemotoxin), and the other 

 on leukocytes (leukocidin). 



An anti-hemotoxin that counteracts the effects of the toxin may be 

 produced experimentally, and in human staphylococcus infections the 

 demonstration of such antihemotoxic substances in the blood-serum 

 may be of aid in making the diagnosis of staphylococcus infections. 

 This antistaphylolysin may be found normally in small amounts in the 

 serum of man and horse, and when anti-hemotoxic tests with human 

 serum are made, a normal control should always be included. Anti- 

 leukocidins have also been produced, but are not of practical im- 

 portance. 



The hemotoxin is readily formed in cultures of staphylococci ; 

 roughly, the amount produced depends upon the virulence of the culture. 

 In human cases of staphylococcus infections this toxin produces hemoly- 

 sis in vivo, and is partly responsible for the grave anemia that is fre- 

 quently present. 



6. Streptolysin. The grave systemic symptoms that so frequently 

 accompany slight streptococcus lesions are strong indications that these 

 microorganisms produce a powerful diffusible poison, although extensive 

 researches into the nature of these poisons have not given us any clear 

 understanding of the subject. 



Streptococci may yield soluble toxins that, when administered to 

 guinea-pigs, produce rapid collapse and death. While these toxins are 

 not comparable in potency to the soluble toxins of diphtheria and 

 tetanus, they have, nevertheless, been differentiated from the endo- 



