138 BACTERIOLYSINS AND HEMOLYSINS 



On close study of the above experiment, it will be noted that even in 

 those cases in which the animals died of the infection, bacteriolytic phe- 

 nomena were not altogether absent. They occurred particularly in the 

 beginning and were incomplete. This can be considered as evidence of 

 the fact that even normal animals possess a certain supply of bacteriolysins 

 which are, however, readily exhausted. This amount of normal bac- 

 teriolysin in serum varies greatly with the species of animal; thus the 

 sera of man and rabbit contain very little normal bacteriolysins for cholera 

 and typhoid, while horse's serum is well supplied with the same. 



According to Kolle, a loopful of virulent cholera vibrios is destroyed in the peri- 

 toneal cavity of a guinea-pig, by 



0.005 to o.oi c.cm. of normal horse's serum, 

 o.oi to 0.02 c.cm. of normal ass serum. 

 0.02 to 0.03 c.cm. of normal goat's serum, 

 o.i to 0.3 c.cm. of normal rabbit's serum. 



The protective action of bacteriolytic sera differs very essentially from 

 that of antitoxic sera. For the latter, the law of multiple proportions holds 

 true; a stronger dose of toxin is neutralized by a proportionately larger 



amount of antitoxin; to bacteriolytic sera this rule does not 

 Endotoxin. apply. If the bacteria are increased beyond a certain quantity, 



their dissolution can indeed be accomplished by the addition of 

 sufficient amounts of bacteriolysins, but the animal dies nevertheless. Its 

 peritoneal cavity examined during life or postmortem may be absolutely 

 sterile. Pfeiffer's explanation for this phenomenon is that the endotoxins 

 within the bacteria are liberated by bacteriolysis and kill the animal. 

 Fatal results from endotoxin follow in a similar manner when dead instead 

 of living bacteria are injected. 



Since endotoxins can continue their effective action in spite of the 

 serum, it is evident that the usual bacteriolytic serum lacks the power to 

 neutralize the poisons of the endotoxins. Many investigators have at- 

 tempted to supply this deficiency. (This will be considered later.) 



While bacteriolysis may take place without any resulting protective 

 action, on the other hand a serum may be curative in spite of the absence 

 of bacteriolysis. This is well demonstrated in MetchnikofFs experiment. 



A marked leucocytosis in the abdominal cavity of a guinea-pig 



is produced by the intraperitoneal injection twelve hours 

 mkoff's . . 



Experiment P revlous ly of 5 to 10 c.cm. of aleuronat solution or sterile 



bouillon. Pfeiffer's experiment is then performed. As a rule, 

 bacteriolysis occurs up to a certain point, particularly when cholera 

 vibrios are used; most of the bacteria, however, retain their form and are 

 taken up by the leucocytes. 



Metchnikoff used this experiment to uphold his theory of the signifi- 



