XVI. OBSERVATIONS ON THE SINGLE NATURE OF 

 HEMOLYTIC IMMUNE BODIES, AND ON THE EXIS- 

 TENCE OF SO-CALLED "COMPLEMENTOIDS."* 



By FREDERICK P. GAY, M. D. 



This article deals primarily with two hemolytic phenomena, by 

 means of which two hypotheses have apparently been proved 

 experimentally. Although I have dealt in each instance with the 

 classical example only, my results are doubtless applicable to 

 hemolysis in general. 



I. The Nature op a Hemolytic Immune Body as regards its 

 Reactivating Sera. 



As Bordetf was first to show, hemolysis of rabbit red blood cor- 

 puscles may be accomplished, in the presence of a suitable heated 

 immune body (sensibilisatrice), by any one of several alexins, even 

 by rabbit alexin; in this latter case, however, the amount of immune 

 body necessary to produce hemolysis is sensibly increased over the 

 amount necessary when guinea-pig alexin is used. Ehrlich and 

 MorgenrothJ were able to corroborate this observation and also 

 to add several analogous instances which show clearly that the 

 relation of such immune body dosage is a variable one. The 

 explanation which they offer, in harmony with their "Lateral- 

 chain theory," is briefly as follows: In a given case the amount 

 of heated serum of a guinea-pig immunized against rabbit corpuscles 

 necessary to hemolyze a given dose of rabbit washed corpuscles is 

 ten times as great if rabbit "complement" (fresh serum) is used to 

 reactivate, as when guinea-pig "complement" is used. This is due 

 to the fact that a given immune serum contains a series of " partial 

 immune bodies," all active against the specific corpuscles, but 



* Centralbl. f. Bakt., etc., I. Abt. Originate. Bd. XXXIX, 1905, p. 172. 

 t Bordet, see p. 134. 



t Ehrlich and Morgenroth, See Collected Studies on Immunity, Ehrlich- 

 Bolduan, John Wiley & Sons, p. 67. 



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