METHODS OF ELICITATION OF PHENOMENON 209 



disruption of the elastic fibres. In the throml^i only clinnps of 

 fibrin were seen; fibrin strands were not demonstrable. 



Endothelial alterations of the vessels or (glomerular capillaries 

 ^vere not noted, excej^t in those instances in which necrosis had 

 inxohed the structine. 



Inasmuch as the animals presenting renal lesions were sacri- 

 hced A\ithin twenty-lour hoins after the second intraxenous in- 

 jection of bacterial Hltrate, the further course of the vascular 

 alterations xvas not obserxed by Gerber. Both Apitz and Gerber 

 agree that the criteria for recognition of phenomenon of general 

 vascular reactivity elicited by way of the general circulation, lie 

 exclusi\ely in the production of the above described kidney al- 

 terations inasmuch as in other organs lesions may be obserxed 

 also following a single injection of bacterial filtrate. 



Recently, Apitz (19350) , extended the criteria to include, in 

 addition to the renal lesions, death of the animal within forty- 

 eight hours after the second injection. Judging from my own 

 experiments, stich criteria may prove unreliable inasmuch as 

 there is observed an extreme irregularity of the lethal effect of 

 the bacterial filtrate. Gerber also reports that the death of the 

 animal was foinid to foUoxv a single injection xvith the same 

 regidarity as txvo injections. Large doses of filtrate, particularly 

 those of meningococcus and B. typJiosus, may lead to death of 

 the animal more often than a similar quantity given in two di- 

 \ided doses. In the experiments to be described in more detail 

 in Chapter vni, it xvas observed that in certain proportions 

 mixttnes of B. t\l)hosus culture filtrates xvith homologotis neu- 

 tralizing antisera })ossess a high phenomenon-producing and low 

 lethal potency. In studies on the general phenomenon Gerber 

 took adxantage of this fact and stibstittited one injection, either 

 the preparatory or the pro\'ocative one, by B. typhosus active 

 principles partially neutralized xvith homologotis horse antisera. 

 This procedure permitted him the use of much larger doses of 

 the filtrate xvith an appreciable reduction in the mortality rate. 

 Partial neutralization of the filtrate reduced the lethal effect to 

 a greater extent than the concentration of factors responsible for 

 elicitation of lesions in the internal organs of the rabbit. Typical 

 renal lesions were ol)ser\ed in a fairly high percentage of stu^- 

 viving rabbits. 



In additicmal studies, Apitz (1935^) reported experiments de- 

 signed to afford additional evidence that the macroscopic and mi- 



