408 INFECTION AND RESISTANCE 



correlated their animal experiments carefully with the action of the 

 sera in vitro upon the blood elements of rabbits, and utilized the 

 property of hirudin to inhibit the coagulation of blood, finding, in 

 the case of dog serum, that injections of hirudin, while not always 

 preventing death, at any rate prolonged life or necessitated an in- 

 crease in the lethal dose. The conclusions of these authors are as 

 follows : "Death following the injection of foreign serum is brought 

 about by obstruction of the pulmonary circulation either by heaps of 

 agglutinaled erythrocytes or by fibrinous plugs. Dog serum and beef 

 serum represent two different types. In the case of dog serum hem- 

 olysis of the blood cells of the recipient liberates substances at- 

 tached to the stromata, which hasten coagulation. In consequence 

 fibrin is formed which is carried into the pulmonary vessels and 

 occludes them. In the case of beef serum death is due to hemag- 



giutination." 



The more recent understanding of the liberation of toxic bodies 

 from blood cells by immune hemolytic sera, especially by the experi- 

 ments of Friedemann cited above, have rendered it likely that a 

 similar anaphylatoxin formation from the cells of the recipient may 

 lie at the bottom of the toxic action of normal sera. And it is a 

 fact, indeed, that such toxic sera are always hemolytic for the cor- 

 puscles of the susceptible animal. 



An analysis of the toxic action of certain normal sera from this 

 point of view has been made by Uhlenhuth and Haendel, 73 who, in 

 studying the necrotizing action of beef serum injected into guinea 

 pigs, attribute this action of the serum to a "complex process de- 

 pending upon the cooperation of complement/' but not identical 

 with the hemolytic mechanism. The toxic action of such serum, how- 

 ever, they separate from the necrotizing action, concluding that this 

 is independent of complement, and more thermostable than either 

 the mechanism causing necrosis or that responsible for hemolysis. 



Kecent studies of the writer 76 on the toxic action of goat scrum 

 for rabbits have shown that, contrary to Loeb, Strickler, and Tuttle, 

 hcmagglutination and blood coagulation can be excluded as causes 

 of death, and that, in agreement with Uhlenhuth and Haendel, the 

 toxic action is due to a proteolytic action on the part of the serum 

 not necessarily identical with the hemolysins, but producing from 

 the protein of the recipient a poison similar to the anaphylatoxins. 

 Unlike Uhlenhuth and Haendel,, however, it seemed clear that the 

 participation of alexin was definitely necessary the process being 

 probably entirely analogous to Friedemami's results with immune 

 hemolytic (cytolytic) sera. The poisonous action of dissolved hemo- 

 globin could be excluded. In principle, therefore, the toxic action 



75 Uhlenhuth and Haendel. Zeitschr. f. Immunitatsforsch., Vol. 7, 1910. 



76 Zinsser. Jour. Exp. Med., Vol. 14, 1911. 



