256 LECTURES ON IMMUNITY 



proof given by Ford and Wassermann, 1 that the agglutinin 

 to chicken erythrocytes, which is found in normal rabbit- 

 serum, is identical with that contained in serum from rab- 

 bits treated with the said erythrocytes, because both are 

 neutralised by serum from chicken treated with rabbit 

 erythrocytes. 



Bordet makes some remarks of great theoretical interest 

 bearing upon the results of his experiments. Ehrlich and 

 Morgenroth 2 found that in the said combination of erythro- 

 cytes and immune-body it was possible to use alexin from 

 goat-serum, although it had a weaker haemolytic action 

 than that from guinea-pigs. They then made experiments 

 with the neutralising action of an antiserum produced by 

 the injection of serum from rabbits treated with bovine 

 erythrocytes into the veins of a goat. They found that this 

 serum (in a given quantity) hindered the haemolysis by 

 alexins from guinea-pigs, but not by that of goat-serum. 

 But as the alexin from goats is much weaker, they used in 

 this special case a much greater quantity of immune-body. 

 Thereby they introduced not alone the immune-body in 

 great quantity, but also the substances contained in normal 

 rabbit-serum which are able to neutralise the antiserum. 

 Bordet explains in this simple manner that the antiserum 

 Jhad no action in this case, and rejects the explanation of 

 Ehrlich and Morgenroth, who assume that the different 

 effect is due to the presence of two different kinds of im- 

 mune-bodies in the preparation, of which the one gives 

 compounds with the alexin from guinea-pigs and with the 



J Ford: Zeitschr. f. Hygiene, 40. 363 (1902); Wassermann: ibidem, 42. 

 267 (1903). 



2 Ehrlich and Morgenroth: Berl. klin. Wochenschrift, Nos. 21 and 22 

 (1901). 



