98 IMMUNE SERA 



ployment of a large dose is of paramount importance. 

 So far as the antitoxic action is concerned * one 

 cannot do harm by giving a large excess. Con- 

 cerning the action of bactericidal sera, however, 

 the literature contains a number of examples which 

 indicate that here an excess of immune serum is 

 occasionally injurious. Perhaps the earliest proto- 

 col of this kind is that published by Loffler and 

 Abel 2 on their experiments with bacillus coli and a 

 corresponding immune serum. Out of nineteen 

 guinea pigs which had been inoculated with the 

 same amount of culture and had received varying 

 amounts of immune serum, only six animals were 

 protected, those which had received doses of 0.25 

 c.c, to 0.02 c.c. Eight animals with larger doses, 

 as well as five with smaller doses of serum died. 

 Neisser and Wechsberg 3 encountered the same 

 phenomenon in bactericidal test-tube experiments, 

 and concluded as a result of their experiments 

 that the only satisfactory explanation was one based 

 on the views of Ehrlich and Morgenroth. In Fig. 

 10, A II represents schematically a bacterium a 

 with a number of receptors; for there are many 

 reasons for assuming that each bacterium possesses a 



1 We shall discuss the rash production, or " serum sickness," 

 page 138. 



2 F. Loffler and R Abel, Centralblatt Bacteriol., 1896, Vol. 

 xix, p. 51. 



8 M. Neisser and F. Wechsberg, Munch, rned. Wochen- 

 schrift. 1901. No. 18. 



