66 EVOLUTION OF THE INFECTIOUS DISEASES 



this antigen with antibody in excess do not produce an active 

 anaphylactic state. In typhoid, however, we may suppose 

 that the bacterial antigen secretion is not pathogenic for 

 normal tissue or else that this secretion is not the whole 

 antigen and that the pathologic symptoms which are mani- 

 fested at the moment of appearance of antibodies in excess 

 can be only the result of the combination of these antibodies 

 with antigens produced by bacteriolysis. Thus the syndrome 

 of the period of disease in typhoid in exclusively anaphylactic. 

 From the point of view of pathogenicity we may thus review 

 the two cases by the following f ormulse : 



Diphtheria: Toxin + Normal antibody = Disease. 

 Toxin + Antibody in excess = Immunity and cure 

 Typhoid: Toxin (?) + Normal antibody = O ? 

 Products of bacteriolysis + Normal antibody = Incubation. 

 Products of bacteriolysis + Antibody in excess = Immunity and 

 anaphylaxis. 



Thus we have seen that in typhoid there is no toxin- 

 secretion nor bacterial-antigen analogous to that of diph- 

 theria or if there is one, it is neutralized at the end of the 

 incubation period by the appearance of antibody in excess 

 (as in diphtheria) and can no longer produce any apparent 

 disturbance. If at this moment it becomes pathogenic it 

 will produce only anaphylactic disturbances. But in typhoid 

 there is certainly penetration and multiplication of bacteria, 

 or at least of products of bacteriolysis in the form of albumin 

 and it is absolutely certain that there are albumins which 

 cause disturbances characteristic of the period of disease as 

 in the case of every other heterologous albumin when com- 

 bined with its antibodies in excess. 



Thus we may conclude with certainty that in typhoid the 

 disease consists of an anaphylactic crisis which is chronic or, 

 in other words, of a succession of anaphylactic crises which 

 are determined at each moment by the three following factors: 



1. The appearance of the albumin antigen as a result of 

 the'multiplication of bacteria. 



| 2. The quantity of antibodies in excess formed by the 

 organism. 



