TYPHOID FEVER 63 



The first bacteria which penetrate into the blood are 

 engulfed by leukocytes and taken to the hemopoetic organs 

 where they are more or less completely destroyed and where 

 those which remain viable produce little foci of infection 

 and lesions. During all this period typhoid antigens, bac- 

 terial secretions as well as products of bacteriolysis are found 

 in excess of the normal antibodies which preexist in the cells 

 of every organism susceptible to the action of antigens. The 

 areas of congestion are caused by the fixation u en surcharge" 

 of antigens by normal antibodies. Thus, for example, when 

 an injection of antigen is made into or under the skin, a mild 

 local congestion is produced; but when it is given into a vein, 

 there will be no appreciable reaction because here the antigen 

 will be distributed to a much larger number of cells and will 

 therefore never be in excess. 



Under the continued action of new quantities of antigen 

 which increase steadily until the spontaneous death or destruc- 

 tion of the bacteria, there are formed in the organism larger 

 and larger quantities of antibodies. The excess of these is at 

 first stored "en surcharge" in the cells in which it is formed; 

 but after a certain maximum is reached, this excess is finally 

 thrown off into the blood by a series of sudden discharges. 



At a certain given moment the antibody thus appears in 

 excess in the blood in spite of the continued multiplication 

 of bacteria and we must necessarily conclude that the pro- 

 duction of antibody is more rapid than that of antigen. The 

 moment at which we begin to find antibody in excess in the 

 blood coincides generally with the appearance of the first 

 severe symptoms which characterize the disease. This is 

 the end of the period of incubation and the beginning of the 

 period of disease. 



If then one could describe the condition in which the 

 infected organism is found from the point of view of immunity 

 and anaphylaxis or if we could stop the evolution of the 

 infection at the end of the incubation period or at the moment 

 of the appearance of antibodies in excess we would find that 

 the organism had developed a greater resistance to a new 

 infection, in other words, that it had acquired a certain 

 degree of active anti-infectious immunity, and also that it 

 had become susceptible to active anaphylaxis. 



