Splanchnic Removal of Bacteria from Blood Stream of Pyrogen-Tolerant Rabbits. ∗

Discussion and Conclusions

Beeson(2) has shown that in animals made tolerant to the pyrogenic effect of typhoid vaccine, there is an increased disappearance of the pyrogenic material from the blood stream. The increase in disappearance rate is blocked by the administration of thorotrast. He interpreted this as an indication that the reticuloendothelial system removes the pyrogenic material from the blood stream and that it does so with increased efficiency on repeated contact with the pyrogen, thus leaving less and less pyrogen in the blood stream to damage other susceptible tissues. More recent studies by Bennett and Cluff(l) have shown that rabbits made tolerant to pyrogens become non-reactive also to the Shwartzman phenomenon. Both of these effects are blocked by the injection of thorotrast(2,3); as is the removal of bacteria from the blood stream(4). However, although there seem to be some similarities between the characteristics of resistance to the Shwartzman phenomenon and resistance to pyrogen effect, the third effect (i.e. removal of bacteria from the blood) does not show a cross-relationship, at least insofar as alteration of bacterial removal by pyrogen-tolerance is concerned. The extent of splanchnic removal of bacteria from the blood stream of pyrogen-tolerant animals is not significantly different from the removal rate observed in the control groups.