PLURALITY OF COMPLEMENTS OF THE SERUM. 205 



This shows us that the two complements I and II (normal hsemoly- 

 sins) cannot by these experiments be differentiated from each other, 

 that the other three complements, however, can absolutely be distinguished 

 by their behavior, not only from one another but also from the first group. 

 Hence in the five different combinations the existence of at least four 

 different complements is positively demonstrated. And that the two 

 normal haemolytic functions of goat serum are also effected by two 

 different complements follows from a previous experiment of Erhlich 

 and Morgenroth. 1 These authors showed by filtering a normal goat 

 serum through Pukall filters, that the filtrate contained exactly the 

 same amount of complement for guinea-pig blood, whereas the com- 

 plement for rabbit blood was almost entirely absent. E. Neisser 

 and Dor ing 2 have confirmed this result in the case of human serum. 



The necessary consequence, therefore, of our experiences with 

 goat serum is the demonstration of the fact that in the five completions 

 examined, five different complements of the goat serum come into play? 



We have also examined the complementing properties of the 

 sera of other animal species, and have arrived at results which abso- 

 lutely contradict the Unitarian view of the complements. These 

 experiments concern first the serum of rabbits. We shall proceed 

 from the fact determined by Schiitze and Scheller 4 under Wasser- 

 mann's direction, that, following intravenous injections of goat blood, 

 the rabbit serum completely loses its property to dissolve goat blood. 



The question now was whether the rabbit serum had been 

 deprived merely of this one complementing function, or whether it 

 had also suffered loss in the rest of its complement properties. 



We therefore tested the power of rabbit serum, before and after 

 the injection of goat blood, to activate the immune body obtained 

 by immunizing rabbits with ox blood. As the essential result of 

 our numerous investigations we established the fact that the com- 



1 See page 56. 



2 E. Neisser and Doring, Berl. klin. Wochenschr. 1901, No. 22. 



3 Through the courtesy of Dr. Wendelstadt in Bonn, we learn that that 

 investigator, by means of an interesting method, has also succeeded in demon- 

 strating a number of complements in goat serum. He immunized a goat with 

 several species of blood and was then able by means of chemical and thermic 

 influences to separate the complements fitting the immune bodies produced. 

 See Centralblatt f. Bacteriologie, in which this study is about to appear. 



4 Schiitze and Scheller, Experimentelle Beitrage zur Kenntniss der im 

 normalen serum vorkommenden globuliciden Substanzen, Zeitschrift f. Hygiene, 

 Vol. 36, 1901. 



