TOXIN AND ANTITOXIN 



ammonia present in a series of mixtures in which increasing quanti- 

 ties of boric acid were added to a constant quantity of ammonia, and 





CURVE EEPRESENTING THE NEUTRALIZATION OF TETANOLYSIN BY DIFFERENT QUAN- 

 TITIES OF ANTITOXIN. 

 Taken from Arrhenius, "Immunochemistry," Macmillan, 1907, p. 175. 



the values so obtained corresponded with much accuracy to those re- 

 sulting from measurements of toxicity upon red blood cells. The fol- 

 lowing table taken from Arrhenius and Madsen illustrates this : 



TOXICITY (Q) OF 0.1 N. NH 3 (1 EQUIVALENT) WITH N EQUIVALENTS OP BORIC 

 ACID. (Taken from Arrhenius, loc. cit. p. 176.) 



Here, in the last column, there is indicated the proportion of 

 toxicity which is neutralized by the successive addition of % of an 

 equivalent of boric acid. The first additions lower it to a degree 

 proportionate to the amount of acid added; the next additions neu- 

 tralize it to a much slighter degree, and, as further additions are 



