NEUTRALISATION OF PLEMOLYSINS 189 



The presence of protein, as egg-albumen or normal 

 serum, protects the erythrocytes from the attack of bases 

 and much more still from that of lysins of bacterial origin. 

 Probably this action consists chiefly in a diminution of the 

 velocity of reaction. If great quantities of normal serum 

 are added, they act as an antitoxin. 



In mixtures containing heavy doses of poison and of 

 antitoxin, the velocity of reaction is very much retarded, 

 probably because of the presence of large quantities of 

 protein which as impurities accompany the preparations of 

 poison and of antitoxin. 



The antitoxic influence of normal serum was first ob- 

 served by Ehrlich, 1 who employed horse-serum against 

 tetanolysin. Neisser and Wechsberg 2 found a similar in- 

 fluence of horse-serum or human serum on staphylolysin. 

 Madsen and I 3 observed a similar action of chicken egg- 

 white on tetanolysin ; still greater is the influence of egg- 

 white from duck's eggs, according to P. T. Miiller. 4 

 Marshall and Morgenroth 5 made similar observations on 

 the action of different sera on different compound haemo- 

 lysins (cf. Chapter VIII). The normal serum of the 

 horse, rabbit, and man are the most efficient, that of 

 pigeons, mice, and geese less, while that of sheep is nearly 

 insensible. According to P. T. Miiller, the antitoxic ac- 

 tion against tetanolysin is probably due to the presence of 

 cholesterin in the horse-serum or egg-white. Against the 

 generalisation of this view it may be pointed out that, ac- 



1 Ehrlich : Berl. Klin. Wochenschrift^v. 12 (1898). 



2 Neisser and Wechsberg: Zeitschr.f. Hygeine, 36. 314, etc. (1901). 



3 Arrhenius and Madsen : Festskrift, III. 37 and 43 (1902). 



* P. T. Miiller: Centralbl. / Bakteriologic, I. 34. 567 (1903). 



6 Marshall and Morgenroth: Ztitschr. f. klin. Mcdicin, 47. fasc. 3 and 4. 



