40 TOXINES AND ANTITOXINES. 



to find L + . This can cause no alteration in the compounds 

 already formed between toxine and antitoxine or protoxoid and 

 antitoxine, which might make them yet combine with fresh doses 

 of toxine added, and so cause them to disappear as regards L + 

 i.e., as soon as the amount of poison added to the neutral mixture 

 reaches one lethal dose, L + is reached, as is demanded by theory 

 for pure poisons ; this may be expressed graphically by the 

 equation 



90 T-A + 10 P-A + 1 Toxine = L + . 



Thus the presence oj protoxoid cannot cause L - L + (D) to be 

 greater than one lethal dose. 



The syntoxoids have just as little influence in raising the value 

 of D. They, too, are not influenced in their combination by the 

 addition of toxine, and L + is reached by the addition of new 

 poison so soon as one lethal dose is added to L . 



Thus all the secondary toxoids are without influence upon D. 



We find quite a different state of things when we examine the 

 behaviour of toxones in this respect. 



Let us now leave out of consideration the toxoids, which have 

 no bearing upon this question, and represent a neutral mixture 

 of toxine and toxone with antitoxine (L ) by the following 

 equation : 



90 T-A + 10 Toxone-A = L . 



We then add fresh quantities of poison. If, in the first place, 

 we add a quantity containing exactly one toxic unit, we find 

 that L + is by no means reached by that addition ; for the toxine 

 liberates a toxone unit from its combination with the antitoxine ; 

 and, instead of the free toxine added, we find a free toxone, as 

 represented in the following equation : 



90 T-A +10 Toxone-A + 1 Toxine 

 = 91 T-A + 9 Toxone-A + 1 Toxone (free) = L . 



And so the process continues until the whole of the toxones are 

 free. Then, and not till then, the next toxic unit produces L + . 



100 T-A + 10 Toxones (free) = L . 



100 T-A + 10 Toxones + 1 Toxine = L + . 



According to this equation, we should thus have to add, not 

 one, but eleven, toxic units to L before reaching L + , D being 

 thus equal to 11. 



We see then that toxones have the property of raising the 



