406 INFECTION AND RESISTANCE 



searches have appeared during the last two years in which the prob- 

 lem has been approached by different routes, but in which the gen- 

 eral conclusions show much agreement. Coca, 69 investigating the 

 cause of death following the injection of washed blood cells into ani- 

 mals of different species, concludes that in these cases death is due to 

 mechanical obstruction of the pulmonary circulation owing to ag- 

 glutination of the injected cells. It is important to note, however, 

 that he adds in his conclusions the following paragraph: "The 

 mere presence of specific agglutinins does not suffice, in the injection 

 of 'toxic' erythrocytes, to occlude the pulmonary circulation. The 

 cooperation of another factor must be assumed a factor probably 

 found in the capillary walls/ 7 



Loeb, Strickler, and Tuttle 70 investigated the cause of death fol- 

 lowing the injection of normal dog and beef sera into rabbits. They 

 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 

 agglutinated 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- 

 glutination." 



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, 71 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 



69 Coca. Virchow's Archiv, Vol. 196, 1909. 



70 Loeb, Strickler, and Tuttle. Virchow's Archiv, Vol. 201, 1910. 



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



