218 CHEMISTRY OF THE IMMUNITY REACTIONS 



capable of taking up certain disintegration products contained in the serum (per- 

 sensitization) which constitute the so-called end-piece, and which produce hemo- 

 lysis by direct hydrolysis or solution of the stroma elements. 



Hemagglutinin. — Agglutination of red corpuscles occurs under 

 the influence of immune serum as well as under the influence of some 

 normal serums. In all respects the principles seem to be the same as 

 those described for bacterial agglutination. The hemagglutinating 

 antibody behaves like the other antibodies and proteins under the in- 

 fluence of chemical and physical agencies, but Landstciner and Jagic 

 have obtained strong agglutinating solutions containing very little 

 protein. BergeF^ contends that hemagglutination is produced by 

 lipase from the lymphocytes, which alters the lipoid membranes of 

 the erythrocytes. Agglutination occurs at much lower temperatures 

 than hemolysis, and also is not checked by heating the serum to 55° ; 

 hence it is possible to observe hemagglutination independent of hemo- 

 lysis. Serums may contain hemagglutinins and not be hemolytic; 

 the'reverse is also true. The conglutmin effect of beef serum (Bordet 

 and Gay) is also observed with corpuscles as with bacteria. As agglu- 

 tination occurs in corpuscles that have been fixed in formalin or sub- 

 limate' it is probably not the proteins that are affected, but some other 

 of the ingredients of the stroma, of which lecithin and cholesterol seem 

 to be the chief. 



Certain vegetable poisons produce agglutination of red corpuscles, 

 especially ricin, abrin, and crotin, and the fact that ricin has httle 

 or no hemolytic action shows the independence of the processes. Anti- 

 sera for these vegetable poisons are also antiaggiutinative, acting, as 

 Ehrlich showed, on the poison and not on the corpuscles. The seeds 

 of many non-poisonous leguminous plants, and also of Solanaceoe, 

 yield extracts that are strongly agglutinative for red corpuscles; in 

 Phaseolus multiflorus the active substance is found in the proteose 

 of the seed, and seems to be a part of the stored food (Schneider).^" 

 It is not present in other parts of the plant. Snake venojus contain 

 agglutinins, destroyed by heating to 75°; their agglutinating power 

 being in inverse ratio to their hemolytic power. Corpuscles aggluti- 

 nated by venoms may be again separated by potassium permanganate 

 solutions. ^^ Silicic acid and certain other colloids may act as agglu- 

 tinins, their effects bearing a relation to the effects of electrical charges 

 upon agglutination of bacteria or of colloids {q. v.).^^ Corpuscles 

 that have been sensitized by hemolytic amboceptors are much more 

 readily agglutinated by salts of heavy metals, especially copper and 

 zinc, presumably because of quantitative alterations in the electrical 

 charge of the corpuscles induced by the antibody.'** 



" Zoit. Iininunitat., 1912 (14), 255; 1913 (17), 109. 



8»,J()ur. liiol. Chom., 1912 (11), 47; l)il)li()grapliv. 



»' .See FlexntT, irniv. of Pmn. Mod. Bull., 1902 (15), .T24 and :J»)1. 



82 S(>e J/indstrinor aiul .JaKJc. Aliiiich. nicd. \\'ocli., 1901 (51), 1185. 



83 lOisiicr and T'lirdcinaiin, Zcit. Iiuniuiiitat., 1914 (21), 520. 



