BACTERICIDAL PROPERTIES OF BLOOD SERUM 155 



producing much, if any, hemolysis. 43 An alexin which may be strong 

 for a given hemolytic complex may be weak for certain bactericidal 

 complexes, or vice versa. Thus there is a large mass of evidence 

 which shows that no two alexins are exactly alike, though the 

 difference between them can, of course, be defined functionally 

 only. 



The difference between the opinions of Ehrlich and his school 

 on the one hand, and the followers of Bordet, on the other, revolves 

 not about this point, upon which all agree, but about the question of 

 whether one and the same serum may contain more than one alexin 

 or complement. Ehrlich and Morgenroth 44 and Ehrlich and 

 Sachs 45 have brought forward evidence from which they deduce the 

 existence of a number of different alexins or complements for hemo- 

 lytic complexes in the same serum. The earlier experiments of 

 Ehrlich and Morgenroth on this question were carried out by means 

 of the filtration of normal goat serum through Pukall filters ; 46 in 

 these it appeared that the serum which passed through the filters was 

 complementary for sensitized guinea-pig cells, while that part which 

 had, in the original serum, activated sensitized rabbit cells was left 

 behind. Similar differentiation of complement they later based 

 'upon experiments with anticomplementary sera which, they showed, 

 did not equally neutralize all the complementary functions of a 

 serum. 



In support of their contention Neisser 47 described two comple- 

 mentary substances in rabbit serum, the one active for bactericidal 

 complexes, the other for hemolytic, and similar experimental evi- 

 dence has been brought forward by Wassermann 48 for guinea-pig 

 and by Wechsberg 49 for goat serum. 



The evidence advanced by these writers is based -chiefly on ex- 

 periments in which it was found that a normal serum which pos- 

 sessed both bactericidal and hemolytio powers could be deprived of 

 the complement for one or the other of these activities only, by ab- 

 sorption with the respective cells. In addition to this, Ehrlich and 

 Morgenroth, Ehrlich and Sachs, 50 Wendelstadt, 51 and others, claimed 

 to have differentiated various complements in the same serum by 

 careful heating, by the action of weak acids or alkalis, or such 

 methods as the digestion of sera by papain. 



43 Browning. Wien. klin. Woch., No. 15, 1906. 



44 Ehrlich and Morgenroth. Berl. kl. Woch., No. 31, 1900. 



45 Ehrlich and Sachs. Berl. kl. Woch., No. 21, 1902. 



46 Sachs. Berl kl. Woch., Nos. 9 and 10, 1902. 



47 Neisser. Deutsche med. Woch., 1900, p. 790. 



48 Wassermann. Zeitschr. f. Hyg., 37, 1901. 



19 Wechsberg. Zeitschr. f. Hyg., Vol. 39, 1902. 



60 Ehrlich and Sachs. Berl. kl. Woch., Nos. 14 and 15, 1902. 



51 Wendelstadt. Centralbl. f. Bakt., I, Vol. 31, 1902. 



